Steam dryer

Heaters can be located in the space between the trms and the dryer housing, where they are not in direct contact with the product, and thermal efficiencies up to 3500 kj/kg (1500 Btu/lb) of water evaporated can be obtained by reheating the air within the dryer. Steam is the usual heating medium. The hi cost of heating electrically generally restricts its use to relatively small equipment. For materials which have a tendency to foul internal heating surfaces, an external heating system is employed. 

Various Types of Steam Dryers.—simple apparatus is a jacketed shallow pan which is shown in Fig. 31. A number of such pans are frequently placed in one chamber, the outlet of which is connected to an exhauster or chimney. The material rests directly on the pan surface or is placed in metallic trays which can easily be handled. Figure 32 describes a trough dryer which may be used in batches or continuously. Here the material is agitated by paddles or screws and the capacity per square foot is therefore much higher than in tray dryers. Steam consumption is high, i,e., from 1.6 to 2.0 lb. per pound of evaporation. 

External surfaces of hot process equipments such as heaters, dryers, steam pipes, and electrical... 

In another type of dryer, steam is used to transfer heat into large steel rolls over which paper is passed at high speed to remove moisture added in the forming process (3). Typically, the paper web temperature is held to about 170°F. Steam is introduced to the rolls at about 50 psig, with about 2.2 pounds of steam needed to remove each pound of moisture. Process boilers are commonly fired by either residual oil or coal, augmented by waste material such as wood chips and spent pulp liquors. 

Steam jacket rotary dryer Steam tube rotary dryer Tray dryer (batch)... 

In general, the dryer steam can be produced by central steam electric stations, heating plants, or any industrial steam systems. The rotating joints to introduce steam into the dryers and the condensate-removing devices must be specially designed, however. 

In a paper machine, the dryers are arranged in groups that have a common steam-supply header. Each group has to operate in such a condition that neither the condensate nor the noncondensables accumulate in the dryer. There are basically two approaches to design the dryer steam and the condensate system. One is the recirculation system in which most of the blow-through is recirculated and the other is the cascade system in which the blow-through steam from higher-pressure sections is used in lower-pressure sections. The recirculation system is more flexible whereas the cascade system is simpler and cheaper [4],... 

Dryer steam should be free of superheat. Although the condensate inside the dryer desuperheats the steam, a separate desuperheater is used in some cases. The effect of superheating above 100°C is controversial. 

Dryers suitable for drying of the biomass include batch through-circulation dryer (perforated floor bin dryer), PMB or continuous through-circulation dryer, direct rotary dryer (rotary cascade dryer), indirect rotary dryer (steam-tube rotary dryer), fluidized bed dryer (pressurized steam fluid bed dryer), and pneumatic conveying dryer (flash dryer) (Amos 1998 Brammer and Bridgwater, 1999 Wimmerstedt, 2006 Roos, 2008). Drying media can be flue gas, hot air, or superheated steam. 

Continuous fluid-bed dryers, steam tube rotary dryers, and rotary dryers can be designed to provide medium residence time (of the order of minutes). 

Hair dryer/steam Glass-reinforced/ Surface finish, temperature... 

Principal application areas are in water distribution, electrical-electronic applications, business machines, and automobiles. Water distribution applications include pump housings, impellers and filters, shower heads, faucets, valve handles, and other plumbing fixtures. Among the applications in the electrical-electronic areas are cabinets and internal television and radio parts, lighting fixtures, connectors, jimction boxes, wiring ducts, cable covers, protective devices, and motor housings. Noryl is used in many small appliances and personal care products, especially those involving exposure to heat and moisture (food processors, hair dryers, steam irons, hot combs, etc) and in console and decorative trim in... 

Example 6.6. The following model of an integrating process is a modified version of the transfer function presented in EnTech (1993) for the dryer steam pressure associated with paper machine dryer cans. We have added... 

STEAM. H2O. In laboratory tests under static conditions, alloy 3003 was found to be resistant to pure steam over distilled water at temperatures up to 268 C (514°F). In fact, aluminum alloys exposed to steam at these temperatures had improved resistance to corrosion by other environments because of the increased thickness of the oxide film on the surface. In the same tests, steam at 268°C (514°F) was corrosive. High pressure steam can erode aluminum alloys by impingement corrosion erosion, particularly when the jet of steam is perpendicular to the surface. Aluminum alloy equipment including heat exchangers. dryers, steam jacketed kettles, piping have been used to handle steam in the petroleum, chemical and food processing industries. See also Ref (1) p. 144, (2) p. 778, (4) p. 49, (7) p. 175. 

Size reduction, dryer (steam, indirect 14 Steam reforming, WGS, acid gas... 

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