Feed arrangement

Many other mixed-feed arrangements are possible which combine the individual advantages of each type of arrangement. Figure 3.13 shows a three-stage evaporator in temperature-enthalpy terms, assuming that inlet and outlet solutions are at saturated conditions... 

Another factor that can be important in the design of evaporators is the condition of the feed. If the feed is cold, then the backward-feed arrangement has the advantage that a smaller amount of liquid must be heated to the higher temperatures of the second and first stages. 

Finishers. Magnetic finishing dmms are designed to produce the highest possible iron content in the concentrate. Typically, the feed size has been reduced to a nominal size of —74 fim (—200 mesh) or —44 fim (—325 mesh) in a ball mill circuit. The feed tank and feed arrangement of the finisher separator is usually of the semicountercurrent design. The objective is to disperse the feed particles in order to obtain maximum rejection of nonmagnetic particles. Both 762 and 914 mm dia dmms have been used in finisher appHcations. Dmm covers frequendy are not used in finisher constmction because of the material size. 

Drum filters commonly are classified according to the feeding arrangement and the cake-discharge technique. They are so treated in this subsection. The characteristics of the shiny and the filter cake usually dictate the cake-discharge method. 

FIG. 21-1 Typical feed arrangements for screw conveyors, a) Plain spouts of chutes, (h) Rotary cutoff valve, (c) Rotary-vane feeder, (d) Bin gate, (e) Side inlet gate. (FMC Corporation, Matetial Handling Systems Division. )... 

Generally, chemical feed arrangements and TDS controls are more sophisticated than in LTHW systems and some form of pretreatment is almost always provided. 

Typically, chemical formulations were supplied as balls or briquets and dispensed through bypass feeders or hanging baskets. Alternatively, pulverized or powdered treatments were dissolved in water and pumped to FW tanks or added via drip-feed arrangements. 

These devices have gas and liquid streams which merge, i.e. are fed into each other, e.g. by special dual-feed, triple-feed or multiple-feed arrangements. Both phases are then passed in the same encasing, e.g. the same micro channel. From there, fragmentation of the gas stream occurs, forming a dispersion. 

Against this, it may be necessary with a batch vacuum filter to provide holding vessels for feed, and possibly filtrate and wash. The discharge of solids is intermittent and this may lead to complications in feeding the solids to a continuous dryer or to some other continuous process, and cake hoppers and a feeding arrangement may have to be provided. 

Figure 14.5. Forward-feed arrangement for a triple-effect evaporator...

Consider the autocatalytic reaction A R, with = 0.001 C Cr mol/ liter-s. We wish to process 1.5 liters/s of a C o = 10 mol/liter feed to the highest conversion possible in the reactor system consisting of four 100-liter mixed flow reactors connected as you wish and any feed arrangement. Sketch your recommended design and feed arrangement and determine Af from this system. 

When air classification is employed for ash beneficiation purposes, the mechanism is similar, but a high-performance cyclone is used. An example is shown in Fig. 8. Devices vary considerably in the feed arrangement used, but most employ some mechanism to effectively distribute the ash particles across the profile of the cyclone, such as a rotating cage or distribution plate. The velocity of the feed is controlled to produce the desired size separation whereby fine particles and most of the air migrate to the inner vortex while coarse ash exits the bottom. Air classifiers have been used for many years to control pozzolan fineness simply by removing coarse ash particles, particularly when LOI is not a problem. Air classification is usually not effective for reducing LOI, particularly if the carbon is fine. Some coarse carbon particles may be rejected with the coarse ash, but since the density of the carbon particles is lower than... 

Immediately after the full charge of glycerine has been added and the stirrer stopped, the glycerine feed arrangement should be removed from the nitrator in... 

This suggests that fewer elements will be required at a larger scale however, for a conservative design on scale-up, the same number of elements should be maintained. On scaling up or scaling down, the same mixer type and feed arrangement should be maintained. 

The addition of a third monomer tank to the basic power-feed arrangement expands the possible feed profiles available for investigation. As illustrated in Figure 3, one such arrangement involves a stirred middle tank which receives a monomer mix from the far tank and pumps a varying mixture to the near tank. The arrangement is essentially a power feed on top of a power feed and can be analyzed in the same manner as carried out with the two tank systems, except that C2, the concentration of monomer A in the second (middle) tank is not constant but is given by... 

Figure 3. Three-tank monomer feed arrangement in which the near and middle tanks are stirred during operation...

---