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prilling tower and granulation


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prilling tower and granulation

  1. 1. Prepared by Mussab jaffar Farhad Rafique Muhammad yousaf farooq bashir Khalid nawaz
  2. 2.        1) What are prills and Prillings 2)Why we are studying prillings 3) Prilling Tower…? 4)what are grains and granulation 5)why we study granulation 6) Granulator…? 7) And their Industrial applications
  3. 3. A prill is small agregate of material, most often a dry sphere formed from melted liquid  Soldification of droplets of molten material free falling against Upward stream of air in tower is  called Prilling
  4. 4.   It is more convenient for use , storage and transporting because of their much smaller specific surface area and bulk density Prills of fertilizers are small , easy to handle , easily absorb in land , light in weight , very small impurities etc
  5. 5.   The melt must be sprayed into droplets uniform size as required The sprayed droplets must be fully solidified and cooled in order to avoid bonding of particles with each other and caking on wall
  6. 6.   It 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 collected
  7. 7.    The molten fertilizer is sent on the top of fertilizer plant with the help of centrifugal pump With the help of spryer molten fertilizer is droped from the top in the form drops inside the prilling tower While from the bottom hot air is blown which dries the droplets in the form of solid prills
  11. 11.    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 oil Typical prilling tower produce 200 ton/day of fertilizer
  12. 12.    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 prills 50 m high fertilizer prilling tower produce 2mm size prills while , for explosive particles size of prilling tower is about 10 m to produce small prills
  13. 13.   The 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 problems
  14. 14. Competition from granules  The 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.
  15. 15.    Prilling tower is backbone of fertilizer or any other chemical industry where the final product is in the form of solid prills We can’t imagine a fertilizer industry without a prilling tower The process in prilling tower is continuous , prills moves downward due to gravitational force
  16. 16.      Granulation 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 agent particles 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.
  17. 17. Before granulation After granulation
  18. 18. Dry granulatio n Wet graulati on
  19. 19.    Dry granulation involves granule formation without using liquid solution In dry granulation powder particles may be brought together mechanically by compression into slugs Products maybe sensitive to heat and temperature
  20. 20.   The 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 tablets
  21. 21.     The instrument where the process of granulation take place is called granulator Granulators are classified on the base of shear Shear is mechanical force applied by instrument Granulators may be high shear , low shear or intermediate shear
  22. 22.  There 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 drying
  23. 23.     In this type of equipment, the particles are set into movement by an impeller rotating at a high speed (Approx 50100 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.
  24. 24.   Impeller speed : higher the impeller speed generally denser and smaller granules , lower the speed generally more porous and large particles Chopper speed : there is no effect of chopper speed on granules size but in the case when chopper is large size it act as secondary impeller
  25. 25.   Surface 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 granules
  26. 26.    Fluid bed granulator is low shear type granulator Fluid bed means suspended different particles in air The term fluidization used which means mixing of solids
  27. 27.   The 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
  28. 28.  Granulation 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
  29. 29. > 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 process
  30. 30.      Spray dryer is like a prilling tower but it is used to produce granules Hot solution is sprayed through atomizer from the top Hot air blown in counter or co current manner As water evaporate concentration of solution increase and granules form Granules are separated by cyclone techniques
  31. 31.  Rapid and continues process  Reduce overall cost  No dust formation  Suitable for heat and moisture
  32. 32.      Granulation mainly used in pharmacutical industry Granulation 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
  33. 33.        In prilling tower hot molten liquid and air moves counter current manner It do not involve any binder Its end product is hollow and size is not uniform More tendency for caking and breakage Operation is simple It does not involve agglorimation Less storage life prilling        In granulation powdered particles adhere in form of large particle It involves use of binder End product is solid and size is uniform No breakage and less caking tendency Operation is not simple screening and cyclone separator used It involve process of agglorimation Long storage life granulation