Types of Spray Driers

7/23/2019 Types of Spray Driers

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DRYINGDr. Basavaraj K. Nanjwade M. Pharm., Ph. D

Department of Pharmaceuticsacu!t" of Pharmac"

#mer $!%Mu&htar 'niversit"

(o)ru&, *i)"a.

+%mai! nanjwade)&-mai!.com

2014/03/11 1Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



/#N(+N(0

• Definition of drying

• Importance of drying

• Difference between drying and evaporation• Equipments

• References




Dr"in

• Drying is commonly the last stage in a manufacture process.

• Drying is the final removal of water from material(usually by heat)

• Non%therma! dr"in

1% As quee!ing wetted sponge 2% Adsorption by desiccant (desiccation)

3% E"traction.




Importance of dr"in

• In pharmaceutical technology# drying is carried out for one

or more of the following reasons$

1. %o avoid or eliminate moisture which may lead tocorrosion and decrease the product or drug stability.

2. %o improve or &eep the good properties of a material# e.g.'lowability, compressibility.

3. %o reduce the cost of transportation of large volume

materials ( liquids).4. %o ma&e the material easy or more suitable for handling.

5. reservative.

6. %he final step in Evaporation# 'iltration# rystalli!ation.




Difference )etween dr"in

and evaporation0!. No.

Drying Evaporation*. In dr"in processes# the main operation

usually carried out on so!id materia!s, e.g. powders# or products

In evaporation processes# the mainoperation usually carried out on!i7uid materia!s, e.g. solution# or products

+. Dr"in in most of the cases means theremoval of relatively sma!! amounts ofwater from so!ids

+vaporation include theremova! of !are amounts of

water from solutions.

,. In most cases# dr"in involves the

remova! of water at temperatures

)e!ow its boiling point

-hereas evaporation means theremova! of water )" )oi!in a

solution.

. In dr"in , water is usually removed by circu!atin air over the materia! inorder to carr" awa" the water vapour

-hile in evaporation # water isremoved from the material aspure water vapour mi"ed withother ases.

2014/03/11 %Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



+7uipments

*. Drum dryer ('ilm drying)

+. pray dryer

,. 'ree!e Dryer . %ray drier

/. 'luidi!ed 0ed Dryer

1. 2acuum Dryer

2014/03/11 Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$

&



Drum Dr"er 8i!m Dr"in9

2014/03/11 'Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



Drum Dr"er 8i!m Dr"in9

• It consists of a drum of about 3.4/5*./ m in diameter and+5 m in length# heated internally# usually by steam and

rotated on its longitudinal a"is.

• #peration %he liquid is applied to the surface and

spread to a film# this may be done in various ways# but

the simplest method is that shown in the diagram# where

the drum dips into a feed pan. Drying rate is controlled by using a suitable speed of rotation and the drum

temperature. %he product is scraped from the surface of

the drum by means of a doctor &nife.

2014/03/11 (Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



0pra" Dr"er

2014/03/11 )Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



0pra" Dr"er

• %he spray dryer provides a large surface area for heatand mass transfer by atomi!ing the liquid to small

droplets.

• %hese are sprayed into a stream of hot air# so that

each droplet dries to a solid particle.

• %he drying chamber resembles the cyclone ensuring

good circulation of air# to facilitate heat and mass

transfer# and that dried particles are separated by thecentrifugal action.

• pray dryer can be operated efficiently at variousfeed rates.




ree:e Dr"er




ree:e Dr"er

• 'ree!e drying is a process used to dry e"tremely heat5sensitive materials. It allows the drying # withoute"cessive damage# of proteins# blood products andeven microorganisms# which retain a small but

significant viability.

• In this process the initial liquid solution or suspensionis fro!en# the pressure above the fro!en state isreduced and the water removed by sublimation.

• %hus a liquid5to5vapour transition ta&es place# but herethree states of matter involved$ liquid to solid# thensolid to vapour.




(ra" drier




(ra" drier

• Air flows in direction of the arrows over each

shelf in turn.

• %he wet material is spread on shallow trays

resting on the shelves.

• Electrical elements or steam5heated pipes are

positioned as shown# so that the air is

periodically reheated after it has cooled by

passage over the wet material on one shelf

before it passes on the ne"t.2014/03/11 14Faculty of Pharmacy, Omer Al-Mukhtar

Univerity, !o"ruk, #i"ya$



!uidi:ed Bed Dr"er

2014/03/11 1%Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



!uidi:ed Bed Dr"er

• 6'luidi!ed7 means something that behaves li&e liquid.In the fluidi!ed bed dryer# the mi"ture of solids and

gas behave li&e a liquid and solid are called fluidi!ed.

• It provides good contact between hot air and particlesto obtain efficient drying.

• %he hot air is passed through a mesh# which supports

the conical vessel with a porous base.

• %his vessel is filled with powder to be dried.

• It has wheels and can be clipped to the central plate

by means of a rapid acting ring closure.

2014/03/11 1&Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



;acuum Dr"er

2014/03/11 1'Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$

Steam orWater Jacket

Condenser

Connection to

Vaccum Pump

Condensate

Receiver



;acuum Dr"er

• %his equipment is a good e"ample of conduction

drier. %he vacuum oven consists of a 8ac&eted vessel

to withstand vacuum within the oven.

• %here are supports for the shelves giving a larger areafor conduction heat transfer. %he oven can be closed

by a door.

• %he oven is connected through a condenser and liquid

receiver to a vacuum pump.

• 9perating pressure can be as low as 3.3,53.3, bar# at

which pressures water boils at +/5,/ 3.

2014/03/11 1(Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$



2014/03/11 1)Faculty of Pharmacy, Omer Al-MukhtarUniverity, !o"ruk, #i"ya$

(<$NK Y#'+%mai! nanjwade)&-mai!.com

Types of Spray Driers

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