BUCHI Nano Spray Dryer B-90 - Manual (Page 32)

4 Description of function
32 B-90 Operation Manual, Version B
Use in ‘closed loop’
The Dehumidifier B-296 in ‘closed loop’ set-up allows spray drying of water-organic solvent mixtures,
oxygen sensitive substances or flammable powders under safe conditions.
Dehumidifier
B-296
Nano Spray Dryer B-90
Advanced
Aspirator
O
2
T
OUT
P
N
2
CO
2
T
IN Dongle
Outlet filter
FI
Exhaust
gas
Condensate
T
Cool
Control
Feed
Product
a
b
c
d
e
a Inert gas input
b Dehumidifier B-296 to condensate humidity
c Condensate output to collecting flask d Aspirator to establish gasflow
e Dongle to substitute the missing Inert Loop B-295
signals
Suitable spray drying conditions:
• Water-organic solvent mixture with up to 20 % organic solvent content
• For high boiling solvents mixtures (bp > 70 °C) with up to 50 % organic solvent content
In this configuration the used inert gas (N
2
or CO
2
) is loaded with water-solvent mixture residues from
the spray drying process. After the cooling and drying process the gas flows back to the spray dryer.
NOTE
To increase the efficiency of the dehumidifier significantly, it is recommended to use the optional
preheat exchanger (order no. 040059). The preheat exchanger also safes energy by heating up the
cooled, dehumidified gas again.