Forced circulation
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Forced circulation evaporators use pumps to circulate liquid through tubes at high pressure. This prevents boiling and elevates the boiling point. When the liquid exits the tubes, the sudden pressure drop causes flashing to vapor. This forced circulation and flashing leads to more efficient evaporation. Forced circulation evaporators are useful for evaporating viscous or heat-sensitive substances since the pumping action prevents localized overheating and the rapid flow reduces thermal damage. However, they require more energy due to the power needed to drive the pumps.
Forced circulation
- 2. Name: Reg. No. Smaranika Rahman Zobaida Mostarin Nishi 15103092 15103094
- 3. Forced Circulation Evaporator: Long tube type evaporator where force is used to drive the liquid through the evaporator tubes thus producing high tube velocities.
- 4. 1. Horizontal heating type: 2. Vertical heating type: Types:
- 5. Principle: In forced circulation evaporator liquid is circulated through the tubes at high pressure by means of a pump. Hence boiling does not takes places because boiling point is elevated. Forced circulation of the liquids also creates some form of agitation. When the liquid leaves the tubes and enters the vapor head, pressure falls suddenly. This lead to the flashing of super heated liquor. Thus the evaporation is effected.
- 6. 1. A centrifugal pump. 2. (1-2)/(1-1) shell & tube heat exchanger. 3. An evaporator body with vapor outlet at the top. 4. Deflector plate. 5. An outlet for product discharge at the bottom.
- 7. 1. • Steam→Calendria • Pump →Positive velocity 2. • Mixture →deflector • Cyclone Separator →leaves vapour 3. • Concentrated Liquid → Pump • Concentrated liquid → Collect Working Procedure
- 8. Advantage: • In forced circulation evaporator there is a rapid liquid movement due to high heat transfer coefficient. • Salting, scaling and fouling are not possible due to forced circulation. • This evaporators is suitable for themolabile substances because of rapid evaporation. • It is suitable for the viscous preparation because pumping mechanism is used. Disadvantage: • The equipment is expensive because the power is required for the circulating the liquids. • The hold up of liquids is high.
- 9. Pharmaceutical Application: • If evaporation is conducted under reduced pressure, forced circulation evaporator is suitable for thermolabile substances. • This method is used for the concentration of insulin and liver extracts. • It is well suited for crystallizing operation where crystals are to be suspended at all times.
- 10. Reference: • https://en.wikipedia.org/wiki/Circula tion_evaporator • C.v.s subrahmanyam et al., pharmaceutical engineering principles and practices - evaporation, 2001, page no. 351 - 352. • https://www.indiamart.com/mazda- limited-mumbaimumbai/evaporator- system.html • http://www.pharmainfo.net/book/ph armaceutical-machines/forced- circulation-evaporator