Page 300 - Chemical Process Equipment - Selection and Design

264 DRYERS AND COOLING TOWERS
TABLE g.lS(continued)
(b) Buttner-Rosin Pneumatic Dryer
Metallic Adipic Coal Filter
Stearate Starch Acid Fiber Cake

Method of feed sling sling screw distributor distributor
1.
Material size fine fine -30 mesh -3 in. -30 mesh
Product rate (Ib/hr) 280 13,236 10,000 2610 67,200
Initial moisture (% w/w basis) 40 34 10 62.4 32
Final moisture (% w/w basis) 0.5 13 0.2 10 6
Air inlet temperature (“F) 284 302 320 752 1292
Air outlet temperature (“F) 130 122 149 230 212
Method of heating steam steam steam oil PF
Heat consumption (Btu/lb/water evaporated) 2170 1825 2400 1720 1590
Air recirculation no no no no yes
Material recirculation yes no yes yes yes
Fan capacity (std. ft3/min) 1440 26,500 9500 12,500 27,000
Installed fan HP 15 220 65 60 250
Product exit temperature (OF) 104 95 120 140 158
(Courtesy Rosin Engineering Ltd.; Williams-Gardner, 1971).

(c) Pennsalt-Berks Ring Dryer
Metala Spenta Sewageb Polystyrene
Stearates Grains Sludge Starches Beads
belt back vibratory cascading vibratory
feeder mixer feeder rotary feeder
rotary rotary rotary valve rotary
Method of Feed valve valve valve screen valve
Product rate (Ib/hr) 240 1120 4300 5000 1000
Initial moisture (% w/w basis) 55 80 45 35 2.0
Final moisture (% w/w basis) 1 5 12 10 0.2
Air inlet temperature (OF) 250 500 600 300 175
150 170 170 130 115
Air outlet temperature (OF)
Method of heating steam gas oil steam steam
Heat consumption (Btu/lb water evaporated) 2900 1800 1750 2000 5000
Air recirculation no no no no no
Material recirculation yes yes yes no no
Material of construction ss MSG MS MSG ss
Fan capacity (std ft3/min) 3750 16,500 8250 15,000 900
Installed fan HP 20 75 60 60 7.5
a Ring dryer application.
(Courtesy Pennsalt Ltd.; Williams-Gardner, 1971).

(d) Various Pneumatic Dryers

Air/Solid
Gas Ratio
Tube Tube Rate Gas Temp (“C) Solid Solid Temp (“C) Moisture (%) Water
Dia Height (m3/hr) Rate (m”/kg) Evaporated
Material Location (cm) (m) (NTP) In Out (kg/hr) In Out In Out (NTP) (kg/kg) (kg/hr)
Ammonium
sulphate Japan 18 1 1100 215 76 950 38.5 63 2.75 0.28 1.2 1.5 23.5
Sewage sludge
filter cake U.S.A. - - 1200 700 121 2270 15 71 80 10 5.3 7.2 1590
Coal 6 mm U.S.A. - - 50,000 371 80 51,000 15 57 9 3 1 .o 1.3 4350
Hexamethylene
tetramine Germany 30 38” 3600 93 50 2500 - 48 6-10 0.08-0.15 1.4 1.9 18.1
‘23 m vertical, 15 m horizontal.
(Nonhebel and Moss, 1971).