APV Dryer Handbook - Umbc

56
COST BENEFITS
In comparison to a spray dryer, the Spin Flash dryer has a much shorter residence
time and consequently is considerably smaller and requires less building space.
Its ability to dry to even higher solids than a spray dryer results in operating cost
savings. Table 8 (see page 57) shows a detailed size and cost comparison
based on actual test drying of yellow iron oxide.
It can be seen that the investment in a Spin Flash dryer plant is some 31% lower
than a spray dryer for the same powder capacity and that Spin Flash operating
costs are approximately 28% lower. These figures, however, do not include the
capital investment in filtration equipment.
CONCLUSION
Despite its obvious size and cost advantages, there are many instances when
a Spin Flash dryer cannot replace a spray dryer. Typically, such cases occur when
UNIT
SLUDGE OF VARIOUS METAL HYDROXIDES
DOLOMITE
YELLOW IRON OXIDE
ALUMINA
ALUMINUM SILICATE
INLET AIR TEMPERATURE °F 482 590 617 482 842 536 968 932 410 437 212 914 662 1112 1292
°C 250 310 325 250 450 280 520 500 210 225 100
OUTLET AIR TEMPERATURE °F 185 293 212 194 212 194 338 257 203 203 126 320 311 275 257
°C 85 145 100 90 100 90 170 125 95 95 52
TEMPERATURE OF THE FEED °F 60 60 55 65 60 55 32 55 50 70 70 55 70 60 60
°C 15 15 13 13 15 13 0 13 10 21 21
TOTAL SOLIDS IN FEED % 70 34 35 29 20 58 67 62 50 28 43 35 33 78 65
RESIDUAL MOISTURE % 4.5 0.4 0.6 12.5 5.5 0.3 0 1.0 5.0 9 0.32 2.7 3 0.1 0.5
MEAN PARTICLE SIZE µm 40 15 5 70 20 50 5 15 10 10 16 20 15 5 3
BULK DENSITY gr/cm 3
0.8 0.45 0.3 0.4 0.2 0.45 0.8 0.9 0.7 0.3 0.14 0.76 0.32 1.6 0.6
CALCIUM CARBONATE WITH BINDER
CALCIUM CARBONATE (PURE)
FERRITE
TARTRAZINE (AZO DYE)
FOOD YELLOW (C.I. 15985)
CALCIUM STEARATE
POLYVANADATE
NICKEL CATALYST ON DIATOMACEOUS EARTH
BARIUMSULPHATE
Table 7. Selection of typical Spin Flash dried products and their main operating parameters
TITANIUM DIOXIDE