Partech-size-enlargement.pdf

PARTICLE SIZE ENL ARGEMENT PA R T I C L E T E C H N O L O G Y

SIZE ENLARGEMENT • is the process by which smaller particles are put together to form larger masses in which the original particles can still be identified.

SIZE ENLARGEMENT IS MAINLY ASSOCIATED WITH: AGRICULTURAL INDUSTRY

PHARMACEUTICAL INDUSTRY

SIZE ENLARGEMENT IS MAINLY ASSOCIATED WITH: MINERALS INDUSTRY

FOOD INDUSTRY

SIZE ENLARGEMENT IS MAINLY ASSOCIATED WITH: CERAMICS INDUSTRY

METALLURGICAL INDUSTRY

Sulfur Granules

Ore

Charcoal

PURPOSE OF SIZE ENLARGEMENT • reduction of dust hazard (explosion hazard or health hazard), • to reduce caking and lump formation • increase bulk density for storage • Reduces dust during material processing • to provide a defined metered quantity of active ingredient (e.g. pharmaceutical drug formulations

SIZE ENLARGEMENT METHODS • Granulation • Compaction • Extrusion • Sintering • Spray drying and prilling

COMPACTION

GRANULATION

SINTERING EXTRUSION

PRILLING

SPRAY DRYER

AGGLOMERATION VS GRANULATION

VS

INTERPARTICLE FORCES I. Van der Waals Forces The range of van der Waals forces is large compared with that of chemical bonds. The attractive force, Fvw, between a sphere and a plane surface as a result of van der Waals forces was derived by Hamaker (1937) and is usually presented in the form: Where: Kh = Hamamaker constant R = radius of the sphere y = is the gap between the sphere and the plane

II. Forces due to Adsorbed Liquid Layers particles in the presence of a condensable vapour will have a layer of adsorbed vapour on their surface. If these particles are in contact a bonding forces results from the overlapping of the adsorbed layers. III. Electrostatic Forces It exist either as a result of interparticular friction or through the generation of opposite charge

IV. Forces due to Liquid Bridges dispersing liquid into a powder mass will generally result in a significant increase strength of particle-particle agglomerates

• Liquid bonding between particles: (a) pendular; (b) funicular; (c) capillary; (d) droplet

V. Solid Bridges Granules formed by liquid bridges are usually not the end product in a granulation process. More permanent bonding within the granule is created by solid bridges formed as liquid is removed. Solid bridges between particles may form: crystalline bridges, liquid binder bridges and solid binder bridges.

VI. Comparison and Interaction between Forces

GRANULATION

GRANULATION • Is the process of forming small particles trough agglomeration technique • That is, the process of small particles into grains or granules. • It is a common process in producing solid dosage drugs where it transforms formulations with improved compaction and flow characteristics

BENEFITS OF GRANULATION • Enhanced compressibility in tablet manufacturing process • Uniformly distributes essential ingredients within the granules

2 TYPES OF GRANULATION Dry Granulation and Wet Granulation

I.

DRY GRANULATION TECHNIQUE

• It is the process of forming granules without need for any liquid or solution. • It is a perfect choice for moisture sensitive materials. • Ideally, it is the process of compacting and densifying powder to form granules • Simple and cost effective • Equipment Example: Roller Compactor

Products of Dry Granulation Technique

II. WET GRANULATION • Involves a binder/liquid that causes aggregation of particles • Granulation liquid is a volatile solvent that is easy to remove by drying. • The choice of liquid will depend on the type of material you intend to process • Examples: Ethanol, isopropanol, etc.

MECHANISM OF GRANULATION 1) Wetting and Nucleation – Wetting is the process y which air within the voids between particles is replaced by liquid.

– The rate which wetting occurs is important in granulation for the product quality in the granulation process

Where: Ɛ = granule porosity S = granule saturation Ρs= solid density ρl== liquid density w=liquid level

II. Granule Consolidation • Consolidation is the term used to describe the increase in granule density caused by closer packing of primary particles as liquid is squeezed out as a result of collisions. • Consolidation can only occur whilst the binder is still liquid

• determines the porosity and density of the final granules.

III.GROWTH • As granules grow so do the internal forces trying to pull the granule apart. • It is possible to predict a critical maximum size of granule beyond which coalescence is not possible during collision.

• The parameter which determines whether coalescence will occur is a Stokes number Stk:

low value • impact energy dissipates in a surface liquid film • coalescence occurs Where: X= diameter μ = Viscosity Ρg = density Vapp = velocity

high value • too high impact energy to dissipate = bouncing

IV.Granule Breakage • Breakage (also called fragmentation) is the fracture of a granule to form two or more pieces • Attrition (also called erosion) is the reduction in size of a granule by loss of primary particles from its surface. • breakage may be controlled by altering the granule properties (e.g. increase fracture toughness and increase resistance to attrition) and by making changes to the process (e.g. reduce agitation intensity).

GRANUL ATION EQUIPMENTS D RY & W E T G R A N U L AT I O N

DRY GRANULATION • Commonly used dry granulator – Roller compactors – Tablet press

Roller compactors • used to force fine powders between two counter rotating rolls and presses the raw materials into a solid compact: – Flakes – Sheets

– Strips

A ROLLER COMPACTOR GENERALLY CONSISTS OF THREE MAJOR UNITS. – A feeding system, which converts the powder to the compaction area between the rolls. – A compaction unit, where powder is compacted between two counter rotating rolls to a ribbon by applying a force. – A size reduction unit, for milling the ribbons to the desired particle size.

ADVANTAGES: 

This methodology is especially attractive for drugs, which are moisture or heat sensitive.



Suitable for compounds that either have a low melting point or degrade rapidly during heating



Form porous tablets thus allowing water to penetrate more easily into the tablet, leads to improved disintegration behavior of tablets.

 Environmentally friendly & provides an efficient and easily automated process

 Low operational cost.

minimized dust problems or avoided

 The capping of tablets might also be reduced.  Roll compaction/dry granulation can be used, if the drug or the excipient is poorly flowing or sensitive to heat or moisture.  It can also be used for densification of powders prior to encapsulation.

TABLET PRESS • a mechanical device that compresses powder into tablets of uniform size and weight.

• used to manufacture tablets of a wide variety of materials, including – Pharmaceuticals – Cleaning products – Cosmetics

TABLET PRESS • To form a tablet, the granulated material must be metered into a cavity formed by two punches and a die, and then the punches must be pressed together with great force to fuse the material together.

WET GRANULATION EQUIPMENTS Fluid Bed Granulator Mixer Granulator Tumbling Granulator

Granulator converts fine powders to granules via a series of physical rate processes.

A. FLUID BED GRANULATOR • Refers to a phenomenon where solid particles are subjected to a specified amount of pressure that forces the particles to behave like a fluid.

CHARACTERISTICS: • Product Size: 0.1 to 2 mm • Granule density: Low

• Scale of operation: < 500 kg batch, 50 tph continuous

Top spray

Bottom spray

Tangential spray

3 CRITICAL STAGES: • Using a stream of air to fluidize the bed • Adding a granulation fluid to agglomerate the particles. (Controlled by moisture content.) • Drying processed granules

CONTINUOUS FLUIDIZED BED GRANULATOR

TYPICAL APPLICATIONS: • Continuous: Fertilizers and Detergents • Batch: Pharmaceuticals, Agricultural chemicals

B. TUMBLING GRANULATOR • In tumbling granulators, particles are set in motion by the tumbling action caused by the balance between gravity and centrifugal forces.

• Tumbling granulators operate in continuous mode and are able to deal with large throughputs.

CHARACTERISTICS: • Product granule size is in the range 0.5 to 20mm. • Are good for producing high density “balls” or pellets. • Capable of very large throughputs (up to 0.5 to 800 tph)

TUMBLING GRANULATOR TYPICAL APPLICATIONS: • Fertilizers • Mineral Ores

• Agricultural Chemicals

C. MIXER GRANULATOR • In mixer granulators first the powder is chopped and mixed to produce a fine, free-flowing powder. Then a liquid binder is blended with the powder to produce granules. • High-shear mixer granulators are almost exclusively used in the pharmaceutical industry.

CHARACTERISTICS • Product size 0.1 to 2mm

• Product density: Low density • Have an average processing time of five minutes.

MIXER GRANULATOR TYPICAL APPLICATIONS • Chemicals • Detergents • Pharmacueticals • ceramics

THANK YOU!

REPORTERS • BERCES, RUEMHEL

• BERCES, MARK GIERONNE • BITARA, DANNA EINA • BUNAO, JAY AR

• DIAZ, PAULO