Tests On Plant Dryers

Tests on plant-scale dryers are usually carried out to obtain design data for a specific material, to select a suitable dryer type, or to check present performance of an existing dryer with the objective of determining its capacity potential. In these tests overall performance data are obtained and the results used to make heat and material balances and to estimate overall drying rates or heat-transfer coefficients. Generally, the minimum data to be taken in order to calculate the performance...

Gravity Dryers

Description A body of solids in which the particles, consisting of granules, pellets, beads, or briquettes, flow downward by gravity at FIG. 12-81 Continuous indirect-heated reactotherm. (Krauss Maffei. ) FIG. 12-81 Continuous indirect-heated reactotherm. (Krauss Maffei. ) FIG. 12-82 Mannheim-type mechanical hydrochloric acid furnace. FIG. 12-82 Mannheim-type mechanical hydrochloric acid furnace. substantially their normal settled bulk density through a vessel in contact with gases is defined...

40

Based upon 1200 F air-inlet temperature. With an inlet temperature of 700 F the evaporative capacity would be half that given in the table. Prices are based upon carbon steel construction with cyclone collector (January, 1995). Motors and secondary dust collectors excluded Based upon 1200 F air-inlet temperature. With an inlet temperature of 700 F the evaporative capacity would be half that given in the table. Prices are based upon carbon steel construction with cyclone collector (January,...

4103

*Courtesy of Proctor & Schwartz, Inc. *Courtesy of Proctor & Schwartz, Inc. FIG. 12-56 Section assembly of a continuous through-circulation conveyor dryer. (Proctor & Schwartz, Inc.) FIG. 12-56 Section assembly of a continuous through-circulation conveyor dryer. (Proctor & Schwartz, Inc.) TABLE 12-17 Conveyor-Screen-Dryer Costs* TABLE 12-17 Conveyor-Screen-Dryer Costs* National Drying Machinery Company, 1996. National Drying Machinery Company, 1996. opening timers. For small solids,...

Batch Tray And Dryers

Noodles Dryer Coil Arrangements

Description A tray or compartment dryer is an enclosed, insulated housing in which solids are placed upon tiers of trays in the case of particulate solids or stacked in piles or upon shelves in the case of large objects. Heat transfer may be direct from gas to solids by circulation of large volumes of hot gas or indirect by use of heated shelves, radiator coils, or refractory walls inside the housing. In indirect-heat units, excepting vacuum-shelf equipment, circulation of a small quantity of...

Continuous Tunnel Dryers

Rockwell Rotary Hearth Furnace Drawing

Continuous tunnels are in many cases batch truck or tray compartments, operated in series. The solids to be processed are placed in trays or on trucks which move progressively through the tunnel in contact with hot gases. Operation is semicontinuous when the tunnel is filled, one truck is removed from the discharge end as each new truck is fed into the inlet end. In some cases, the trucks move on tracks or monorails, and they are usually conveyed mechanically, employing chain drives connecting...

Classification Of Dryers

Classification Dryer

Drying equipment may be classified in several ways. The two most useful classifications are based on (1) the method of transferring heat to the wet solids or (2) the handling characteristics and physical properties of the wet material. The first method of classification reveals differences in dryer design and operation, while the second method is most useful in the selection of a group of dryers for preliminary consideration in a given drying problem. A classification chart of drying equipment...

10

SP-51, Marley Co., Mission Woods, Kan., p. 3. From Spray Pond Bull. SP-51, Marley Co., Mission Woods, Kan., p. 3. FIG. 12-23 Spray-pond performance curve. FIG. 12-23 Spray-pond performance curve. FIG. 12-24 Spray ponds cooling curves for steam-condensing service. Temp., Woter Leaving Nozzles, Deg. F. FIG. 12-24 Spray ponds cooling curves for steam-condensing service. L h2 air out - hi air in _ h2 - 41.58 G water temperature in - water temperature out 10 Corresponding...

1283

Barr Rosin FIG. 12-100 P-type ring dryer. Barr Rosin Special designs of spray dryers may provide for cooling air to enter around the chamber, closed systems for the recovery of solvents, and air sweepers or mechanical rakes to remove dry product from the walls and bottom of the chamber. Some are followed by pneumatic conveyors as depicted in Fig. 12-101, in which drying air is diluted with cool air for product cooling before separation. Spray dryers may operate...

Application Of Psychrometry To Drying

In any drying process, if an adequate supply of heat is assumed, the temperature and rate at which liquid vaporization occurs will depend on the vapor concentration in the surrounding atmosphere. FIG. 12-35 Relationship between wet-weight and dry-weight bases. FIG. 12-35 Relationship between wet-weight and dry-weight bases. In vacuum drying or other processes containing atmospheres of 100 percent vapor, the temperature of liquid vaporization will equal or exceed the saturation temperature of...

Mechanicaldraft Towers

Two types of mechanical-draft towers are in use today the forced-draft and the induced-draft. In the forced-draft tower the fan is mounted at the base, and air is forced in at the bottom and discharged at low velocity through the top. This arrangement has the advantage of locating the fan and drive outside the tower, where it is convenient for inspection, maintenance, and repairs. Since the equipment is out of the hot, humid top area of the tower, the fan is not subjected to corrosive...

Schematic Of Tray Dryer

Price includes dryer, 15-lb in2 jacket, drive with motor, internal filter, and trunnion supports for concrete or steel foundations. Horsepower is established on 65 percent volume loading of material with a bulk density of 50 lb ft3. Models of 250 ft3, 325 ft3, and 400 ft3 have extended surface area. Stokes Vacuum, Inc. Price includes dryer, 15-lb in2 jacket, drive with motor, internal filter, and trunnion supports for concrete or steel foundations. Horsepower is established...

Humidity Charts For Solvent Vapors

Humidity charts for other solvent vapors may be prepared in an analogous manner. There is one important difference involved, however, in that the wet-bulb temperature differs considerably from the adia-batic-saturation temperatures for vapors other than water. Figures 12-37 to 12-39 show humidity charts for carbon tetrachloride, benzene, and toluene. The lines on these charts have been calculated in the manner outlined for air-water vapor except for the wet-bulb-temperature lines. The...

Rotary Dryers

Cocurrent Countercurrent

Description A rotary dryer consists of a cylinder, rotated upon suitable bearings and usually slightly inclined to the horizontal. The length of the cylinder may range from 4 to more than 10 times its diameter, which may vary from less than 0.3 to more than 3 m. Feed solids fed into one end of the cylinder progress through it by virtue of rotation, head effect, and slope of the cylinder and discharge as finished product at the other end. Gases flowing through the cylinder may retard or increase...

Batch Throughcirculation Dryers

In one type of batch through-circulation dryer, heated air passes through a stationary permeable bed of the wet material placed on removable screen-bottom trays suitably supported in the dryer. This type is similar to a standard tray dryer except that hot air passes through the wet solid instead of across it. The pressure drop through the bed of material does not usually exceed about 2 cm of water. In another type, deep perforated-bottom trays are placed on top of plenum chambers in a...

Diy Solar Tunnel Dryer

Through Circulation Dryer

FIG. 12-54 Three types of tunnel dryers. Van Arsdale, Food Ind. 14 10 , 43 1942 . FIG. 12-54 Three types of tunnel dryers. Van Arsdale, Food Ind. 14 10 , 43 1942 . ous common materials. Performance data from several commercial through-circulation conveyor dryers are given in Table 12-16. Labor requirements vary depending on the time required for feed adjustments, inspection, etc. These dryers will consume from 0.9 to 1.1 kg of steam kg of water evaporated. Thermal efficiency is a function of...

Use Of Psychrometric Charts

Psychrometric Chart 5000

Three charts for the air-water vapor system are given as Figs. 12-1 to 12-3 for low-, medium-, and high-temperature ranges. Figure 12-4 shows a modified Grosvenor chart, which is more familiar to the chemical engineer. These charts are for an absolute pressure of 1 atm. The corrections required at pressures different from atmospheric are given in Table 12-2. Figure 12-5 shows a psychrometric chart for combustion products in air. The thermodynamic properties of moist air are given in Table 12-1....