Page 293 - Chemical Process Equipment - Selection and Design

TABLE 9.104continoed)

(c) Roto-Louvre Dryers

Material Drled Ammonium Foundry Sand Metallurgical
Sulfate Coke

Dryer diameter 2ft7in. 6ft4in. lOft3in.
Dryer length loft 24 ft 30 ft
Moisture in feed (% wet basis) 2.0 6.0 18.0
Moisture in product (% wet basis) 0.1 0.5 0.5
Production rate (Ib/hr) 2500 32,000 38,000
Evaporation rate (Ib/hr) 50 2130 8110
Type of fuel steam gas oil
Fuel consumption 255 Ib/hr 4630ft3/hr 115 gal/hr
Calorific value of fuel 837 Btu/lb 1000 Btu/ft3 150,000 Btu/gal
Efficiency (Btu supplied per Ib 4370 2170 2135
evaporation)
Total power required (HP) 4 41 78
(FMC Corp.; Chemical Engineers' Handbook, 1984, p. 20.20).

(d) Indirect-Direct Double Shell Dryers

Indirect-Direct Double Shell
Coal Anhydrite Coke

Dryer diameter 7ft6in. 5fr10in. 5ft 10 in.
Dryer length 46ftOin. 35ft0 in. 35ftOin.
Initial moisture content (% w/w basis) 22 6.0 15
Final moisture (% w/w basis) 6 1 .o 1 .o
Evaporation rate (Ib/hr) 5800 2300 1600
Evaporation-volume ratio (lb/ft3/hr) 3.5 3.15 2.2
Heat source coal oil oil
Efficiency (Btu supplied/lb water evaporated) 1250 1250 1340
Inlet air temperature CF) 1200 1350 1350
Outlet air temDerature (OF) 160 160 200
(Courtesy Edgar Allen Aerex Ltd.; Williams-Gardner, 1971).