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Prilling And GranulationPrepared by: Mussab jaffar Farhad Rafique Muhammad yousaf farooq bashir Khalid nawaz1) What are prills and Prillings2)Why we are studying prillings3) Prilling Tower?4)what are grains and granulation5)why we study granulation6) Granulator?7) And their Industrial applicationsObjectives Of Our PresentationA prill is small agregate of material, most often a dry sphere formed from melted liquidSoldification of droplets of molten material free falling againstUpward stream of air in tower is called PrillingIntroduction

It is more convenient for use , storage and transporting because of their much smaller specific surface area and bulk densityPrills of fertilizers are small , easy to handle , easily absorb in land , light in weight , very small impurities etcWhy we need prills

Why we need prillsThe melt must be sprayed into droplets uniform size as requiredThe sprayed droplets must be fully solidified and cooled in order to avoid bonding of particles with each other and caking on wall

Prilling Towerand itsgeneral consederationsIt is cylindrical vertical tower with average hight 75 m , in which urea prilling take place with huge diameter it has two prill sections

One is at top from where molten fertilizer comes and other one at bottom from where prills are collectedConstruction of prilling Tower

FFC prilling tower(in our home town)The molten fertilizer is sent on the top of fertilizer plant with the help of centrifugal pumpWith the help of spryer molten fertilizer is droped from the top in the form drops inside the prilling towerWhile from the bottom hot air is blown which dries the droplets in the form of solid prillsWorking principlePRILLING TOWER:PRILLING TOWER:PRILLING TOWER:This process is widely used in manufacturing of ammonium nitrate, calcium nitrate and fertilizers of N,K and P Prilling also used in explosives industry to produce porous prills of amonium nitrate which will absorb oilTypical prilling tower produce 200 ton/day of fertilizerProducts of prilling tower

In order to produce large size fertilizer prills the hight of prilling should be high and vice versa Higher the hight of prilling tower more will be the strength of prills50 m high fertilizer prilling tower produce 2mm size prills while , for explosive particles size of prilling tower is about 10 m to produce small prillsHight Of Prilling Tower

Inside view of prilling towerThe prill tower is a major source of emission in urea plants. The large volumes of discharged untreated cooling air contain particulate urea dust (1-2kg.t-1) as well as NH3 (0.7-1.0kg.t-1).Increasing the load on a prilling tower can have negative consequences for the prill quality. Higher moisture contents and higher temperatures cause more dust formation and an increased likelihood of caking problemsDrawbacksCompetition from granulesThe quality of prills is significant less than that of granules, the main difference being the lower strength and smaller size of prills. Research has shown that once a farmer has used granules, he will not choose prills again, unless the price is lower. Most new urea plants are large scale granulation plants and are located in low feedstock areas; these plants are export driven and compete or will compete with your prills.

Prilling tower is backbone of fertilizer or any other chemical industry where the final product is in the form of solid prillsWe cant imagine a fertilizer industry without a prilling towerThe process in prilling tower is continuous , prills moves downward due to gravitational force

Importance Of Prilling TOwerGranulation may be defined as a size enlargement process which converts fine or coarse It is the process of collecting particles together by creating bonds between them. Bonds are formed by compression or by using a binding agentparticles into physically stronger and larger agglomerates having good flow property, better compression characteristics and uniformity. The art and science for process and production of granules is known as Granulation Technology.Granulation TechnologyPowder To Grains Before granulation After granulation

Types of granulationDry granulation involves granule formation without using liquid solution In dry granulation powder particles may be brought together mechanically by compression into slugsProducts maybe sensitive to heat and temperatureDry Granulation and its characteristicsThe process in which powder form particles combine to form bigger and solid particle by the process of agglorimation with the help of binding agent like water

It is mainly used in pharmacutical industry , in the formation of tabletsWet Granulation

The instrument where the process of granulation take place is called granulatorGranulators are classified on the base of shearShear is mechanical force applied by instrumentGranulators may be high shear , low shear or intermediate shearGranulatorThere are four major techniques which are used for wet granulation process

1)high shear mixing granulation

2)fluid bed granulation

3)rotating disk method

4)spray dryingGranulation Techniques In this type of equipment, the particles are set into movement by an impeller rotating at a high speed (Approx 50- 100 rpm). Equipment also contains a chopper which rotates at around 1500 4000 rpm [10]. The primary function of chopper is to cut large lumps into smaller fragments thus increases the binder distribution into the blend.High shear mixing granulation

Impeller speed : higher the impeller speed generally denser and smaller granules , lower the speed generally more porous and large particlesChopper speed : there is no effect of chopper speed on granules size but in the case when chopper is large size it act as secondary impellerInput parametersSurface tension: lower surface tension binder will be use in large amount to form granules of same size as compared to binder with high surface tension

Viscosity: a binder with higher viscosity will produce smaller and stronger granulesType of binderFluid bed granulator is low shear type granulator

Fluid bed means suspended different particles in air

The term fluidization used which means mixing of solidsFluid bed granulatorThe powder particles are fluidized in a steam of air , but in addition of granulation fluid sprayed from nozzle on bed of powder

Heated and filtered air is blown in order to mix powder

MechanismGranulation fluid is pumped from a reservior through a spry nozzle positioned over bed of particle the fluid cause the particles to adhere when droplets and particle collide escape of material from chamber is prevented by exaust filter sufficient liquid is sprayed to produce require size particles

> Spray dryer is the process has been used to produce microcapsules , food ingredients , flavors and various biotechnological ingredients

>This process differ from others as it isa continues processSpray dryerSpray dryer is like a prilling tower but it is used to produce granulesHot solution is sprayed through atomizer from the topHot air blown in counter or co current mannerAs water evaporate concentration of solution increase and granules formGranules are separated by cyclone techniquesMechanism

Rapid and continues process

Reduce overall cost

No dust formation

Suitable for heat and moistureAdvantagesGranulation mainly used in pharmacutical industryGranulation time particle size Amount of binder granulation time or size Particle size surface area amount of binder solution granulation time Hydrofobicity hydrophiicity amount of binder solution granulation time Thumb rules for granulationcomparison prilling granulationIn prilling tower hot molten liquid and air moves counter current mannerIt do not involve any binderIts end product is hollow and size is not uniformMore tendency for caking and breakageOperation is simpleIt does not involve agglorimationLess storage lifeIn granulation powdered particles adhere in form of large particleIt involves use of binderEnd product is solid and size is uniformNo breakage and less caking tendencyOperation is not simple screening and cyclone separator usedIt involve process of agglorimationLong storage life

Khalid Nawazcell no:+923007024407institute of chemical engineering and technology Punjab university Lahore Pakistan