Type Separation

The separation method described later in this chapter was gradually developed into its final stage currently used at NCUT by first modifying the ASTM D2007 method, and then developing a miniature version utilizing the SPE (solid phase extraction) methodology that also rendered separation of the olefins. 

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On a land site where space and weight are not normally constraints, advantage can be taken of tank type separation equipment such as wash tanks and settling tanks, and batch processing methods. Such equipment is generally cheaper to maintain than continuous throughput vessels, though a combination of both may be required. 

D. B. Broughton and L. C. Hardison, "Hydrocarbon-Type Separation by Unisorb," Paper presented at the 27th Midyear Meeting of the American Petroleum Institute, Division of Refining, San Erancisco, Calif., May 15, 1962. 

Industrial separations are conducted in gravity or bath separators for a coarse feed, and in centrifugal separators for a fine feed (2,6,10). In gravity-type separators the feed and medium are introduced to the surface of a large quiescent pool of the medium. The float material overflows or is scraped from the pool surface. The heavy particles sink to the bottom of the separator and are removed using a pump or compressed air. The dmm separator (Fig. 13), up to 4.6 m dia and 7 m long, processes approximately 800 t/h, and treats feed of size up to 30 cm dia, operates in the gravity or the... 

Static bath mode. Feed enters at one end of the dmm and the floats exit from the other end. The sink product is removed continuously from the rotating dmm through the use of lifters attached to the dmm which empty into a launder as they move to the top. A modification of the simple dmm separator is the two-compartment dmm separator which allows a two-stage separation. In the cone-type separator (up to 6.1 m in dia and 450 t/h) feed is introduced at the top. The medium in the cone is kept in suspension by gentle agitation. The sink product is removed from the bottom of the cone either directly or by airlift in the center of the cone. The maximum particle size that can be separated is limited to 10 cm. Other separators include the Drewboy bath and the Norwaltbath (2). 

Many other devices are available for laboratory use. These include the Davis tube, Frantz isodynamic separator, laboratory dmm-type separators, low intensity rotating field separator, and superconducting high gradient separator (2). 

Plant capacity is a function of feed size distribution and Hberation. Separators can accept a size range as wide as 50—1000 p.m. Capacities are typically 1000 2500 kg/(h-m) based on rotor length which could be up to 3 m and have dia 150—250 mm. The feed should be as dry as possible because moisture interferes seriously with separation. Heaters are usually provided before the feed enters the charged field. Final cleaning is often conducted in electrostatic-type separators. Electrostatic shape separation, a newer form of ion bombardment separation, involves separation of particles based on shape and density without consideration to conductivities (37). 

In general, pilot-plant space can be divided into five basic types separate buildings, containment cells or barricades, open bays, walk-in hoods, and laboratory areas. A summary of the advantages and disadvantages of each has been given (1). 

Through-type separators are more effective for larger municipal and industrial treatment faciHfies. The operating principles are the same, but flow is through a trough rather than a column. 

Electrochemical Generation of Chlorine Dioxide from Chlorite. The electrochemical oxidation of sodium chlorite is an old, but not weU-known method of generating chlorine dioxide. Concentrated aqueous sodium chlorite, with or without added conductive salts, is oxidized at the anode of an electrolytic cell having a porous diaphragm-type separator between the anode and cathode compartments (122—127). The anodic reaction is... 

Eng. J., 1, 549 (1955)]. Chevron (hook-and-vane) type separators are also used because of their higher-allowable velocities or because of their reduced tendency to foiil with solids suspended in the entrained liquid. 

RIGOROUS METHODS FOR MULTICOMPONENT DISTILLATION-TYPE SEPARATIONS... 

This section also includes a treatment of distillation-type separations from a rate-based point of view that utilizes principles of mass transfer and heat transfer. Section 14 also presents details of that subject as applied to absorption and stripping. 

In Table 13-6, the number of design variables is summarized for several distillation-type separation operations, most of which are shown in Fig. 13-7. For columns not shown in Figs. 13-1 or 13-7 that... 

Media-Particle Size The size of the media particle is important. A relatively coarse medium (minus 100 mesh) is commonly used in larger-volume static-type separators such as cones. However, in dynamic sep-... 

Eleetrostatie-type separation is being tested as an alternath c to the presently used process oF Rotation oF pebble phosphates For eoarser-size Fractions, Advantages sought include reduced reagent costs, a lower water requirement, and Fewer tailings-disposal problems when a part oF the Rotation circuit is eliminated. The largest application oF triboeleetrie separation is in the salt industry where sodium and potassium salts are separated aFter preconditioning. 

The formation of a phenolic resin is often formally separated into two steps, though it probably should be three. If we use a three-step model, the first step is activation of the phenol or aldehyde. The second step is methylolation, and the third is condensation or chain extension. In addition to the clarity provided by the formalism, these steps are also generally separated in practice to provide maximum control of exothermic behavior, with the strategy being to separate the exotherm from each step from that of the others as much as possible. As there are significant differences in the activation step and in the details of the methylolation and condensations steps of novolacs and resoles, we will treat the two types separately. 

The design equations and parameters for the different hoods are quite different, which is the main reason for describing each of these hood types separately. 

A. Trisciani and F. Munari, Characterization of fuel samples by on-line LC-GC with automatic group-type separation of hydrocarbons , J. High Resolut. Chromatogr. 17 452-456(1994). 

Figure 4-28. Wall-wiping centrifugal type separator. Courtesy of Wright-Austin Co.

Baffle Type Separator Speclflcatlona Separator Appllcatloni (Slve Serrlce)... 

In metal-enclosed assemblies, the equipment is contained within a grounded metal enclosure. In metal-clad types, separate compartments are provided for the circuit interrupter, the components connected to one side of the interrupter (e.g. the cable box) and those connected to the other side of the interrupter (e.g. the busbar chamber and the control equipment). 

Second, any valve which has been designed to operate on steam should not be expected to work at its best when supplied with a mixture of steam, water and dirt. A separator, drained through a steam trap, will remove virtually all the water from the steam entering the pressure-reducing set. The baffle type separators are found to be effective over a wide range of flow rates. 

According to the phase diagram which has gained acceptance for this system, the Cr Cj phase never appears at low carbon contents, and a cubic phase of the Cr23Q type separates at 9(X)°C for 0-1% [C], and about 500°C for 0 01% [C]. These points, together with one for 0-3% [C] are shown by... 

A thorough study (cf. Ref. [40]) of failure modes in practice has shown that with this form of separation also the cause of failure has not been the separator the usual failure modes for leaf-type separators, as they have been described for sintered PVC separators, apply here as well. 

Even though this version is not a distinct type of separator, this section is dedicated to it. To all leaf-type separators described, a glass mat can be applied on the side directed towards the positive electrode,... 

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