introduction to drying, large scale industrial equipment & advanced drying technologies
TRANSCRIPT
Hygroscopic materials
Non - Hygroscopic materials
Water in:
• Fine Capillaries
• Cell & fibre walls
• Physical interaction
Bound Water
Vapour pressure of wet solids is less than the vapour pressure
of pure water
Water in void spaces
Un bound Water
Vapour pressure of wet solids is equal to vapour pressure
of pure water
Contains
Contains
Condition
Condition
A. EQULIBRIUM RELATIONSHIPS:-
a) EQULIBRIUM MOISTURE CONTENT(EMC):-
Equilibrium moisture content in a wet mass
At Equilibrium Amount of water = EMC
Vapour pressure of wet mass = vapour pressure of atmosphere
Wet mass
Moisture in the solid > EMC of solid Moisture in the solid > EMC of solid
Moisture Moisture
Desorption Sorption
Behaviour of Desorption & Sorption at a given temperature & humidity of air
Hot air Evaporation
At equilibrium rate of
heating = rate of working
Temperature increases
Temperature increases
Hot air evaporation
First falling rate period
Rate of evaporation> rate of
diffusion
diffusion
Dry spots
CLASSIFICATION OF EQIPMENTS
Material not agitated
Static bed dryers
Batch types:
Tray & truck dryers
Vacuum shelf dryers
Freeze dryers
Continuous types:
Tunnel dryers
Belt dryers
Festoon dryers
Drum dryers
Material agitated
Moving Bed Dryers
Batch types:
Vacuum tumble dryers
Pan dryers
Continuous types:
Rotary dryers
Turbo – tray dryers
Vibrating conveyor dryers
Tower & cascade dryers
Screw conveyor dryers
Fluidized bed dryers
Batch types:
Vertical dryers
Continuous types:
Horizontal vibrating conveyor
dryers
Vertical dryers
Pneumatic dryers
Continuous types:
Spray
Flash dryers
DRYING EQUIPMENTS
APPLICATIONS OF DRYING
Substance Type of deterioration
Crude drugs of animal & vegetable originBlood products, skin, tissueSynthetic & semi-synthetic drugsEffervescent tablets(aspirin, penicillin's)
Chemical decompositionMicrobial growthChemical decompositionChemical decomposition
OPTIMISATION OF DRYING PROCESSES IN THE PHARMACEUTICAL INDUSTRY
Mass-spectrometric online gas analysis ensures better process understanding, simplifiesmonitoring and reduces drying times
The partial or complete removal of solvents is an important process step in manufacturingpharmaceutical intermediate and final products. These drying processes extract water andother solvents from the substrate up to a precisely defined residual value.
The drying endpoint is reached at different times depending on the substance and solventin the batch. The drying endpoint is the point where the residual content of solventdecreases to the required level. The current method to determine the solvent content of thebatch is usually accomplished via manual sampling from the drying apparatus and offlineanalysis in the company laboratory.
REFERENCES:-
www.crcpress.com
www.inprocess-inc.com
www.pharmaceuticalmachinery.in
www.wikipedia.com
www.iptonline.com
www.ima-pharma.com