Typical Applications

1
Typical Applications

• Type Solubility Products
• Forced Circulation Flat, Normal NaCl, Na2SO4,
  or Inverse Citric Acid Na2CO3H20,
  Lactose
• Oslo Growth Type Normal or Flat KCl, (NH4)2SO4
  10 Mole Borax Sodium Sulfate, KNO3
• Draft Tube Baffle Normal or Flat KCl, (NH4)2SO4,
  Boric Acid
• MAP, DAP

2
Common to All Crystallizer Types

• Crystal Residence Time defined by active slurry
  volume.
• Mother Liquor Residence may not be the same as
  crystal residence time
• Heat exchangers are used for both enthalpy
  transfer and fines destruction
• Mixing behavior-Important for supersaturation
  release and minimizing breakage ( secondary
  nucleation)
• Size and stability of metastable supersaturation
  zone places limits on crystallizer design
  choices.
• Crystal size distribution is determined by growth
  rate, nucleation rate, mixing, fines destruction
  and classified
• ( or not) product removal.

3
Design Characteristics

• Forced Circulation- 3 Types of Circulation
  Re-entry types
• Very Stable Operation, long or short retention,
  fines destruction is typically external, integral
  elutriation legs used for size classification.
• Fluidized Suspension Oslo Growth Type-
• Wall salting typical problem, can operate above
  natural magma slurry density, useful for products
  with high attrition. Fluidization flow must match
  heat exchange requirements
• Draft Tube Baffle - Low wall salting, internal
  fines destruction, can operate above natural
  magma density.

4
Manipulating Crystal Residence Time

• Mother Liquor residence time is not equal to
  crystal residence time
• All designs can be adapted to operate above or
  below natural magma density

5
Forced Circulation Types

• Heaters- Many Configurations
• Vertical or Horizontal
• Single or multi-pass
• Shell and Tube or Spiral Channel
• Heating or Cooling
• Body Slurry Re-entry
• Radial
• Tangential
• Draft Tube

6
MSMPR Forced Circulation Crystallization System
with Vertical Single Pass Heater
7
MSMPR Forced Circulation with Tangential Entry
Vapor out
High Velocity At Wall
Vapor Entrainment Disengaging
Steam In
Condensate
Extended Surface Area for Vapor Release
8
MSMPR Forced Circulation Crystallizer with
Horizontal Heater and Draft Tube Circulation
Re-entry
Chevron and/or Mesh Pad
Vapor Entrainment Disengagement
Active Volume
Draft Tube Circulation Re-entry
Boiling Hydrostatic Suppression
Steam
Horizontal Heater
Condensate
9
Forced Circulation w/Draft tubeRe-entry
Mixing Zone
Boiling Suppression
Active Volume
Supersaturation Release Before Magma
Reaches Outer Wall
Steam In
Vertical Heater
10
Forced Circulation Crystallizer with Classified
Product
Mesh and/or Chevron
Entrainment Disengaging Zone
Operating Volume
Boiling Supression
Supersaturated Liquor with Slurry
Elutriating Leg
Normal Solubility Cases Additional Fines
Dissolve Through Heater
Pipe Velocity 8 fps Typical
Dilute Feed for Fines Destruction
Tube Velocity 6-8 fps Typical
11
Typical NaCL External Elutriation Leg
12
Triple Effect Salt Evaporator Flowsheet
13
Forced Circulation with Horizontal Heaters and
Elutriating Leg
Operating Level
Draft Tube Re-entry
Elutriation Leg
Horizontal Heaters
14
Sodium Carbonate MVR Evaporator Flowsheet
15
Draft Tube Baffle (DTB) Crystallizer
Vapor
Chevron and/or Mesh Pad
Vapor Entrainment Disengaging
Crystals Growth Zone Active Volume
Fines Settling Zone
Fines Dissolving Circuit Through Heater
Steam
Horizontal Heater for Boiling Suppression
Condensate
16
DTB Crystallizers with Integral Condensers used
at Low Pressures
Surface Condenser
Barometric Type
17
Standard OSLO Growth Crystallizer
Recirculation Pumping Rate Suspends Crystal
Inventory In Active Volume Growth Zone
Operating Level
Dead No Crystal Zone With Supersaturated Liquor
Steam In
Fines Clarification Zone
Active Volume Growth Zone
21 Head
Condensate Out
18
Modified OSLO Crystallizer
Recirculation Pumping Rate suspends
crystal Inventory in Active Volume Growth Zone
Vapor Entrainment Disengaging Zone
Mixing Zone
Supersaturated Liquor Zone
Boiling Suppression
Fines Clarification Zone
Steam In
Active Volume
Tapered Zone For Classified Bed Expansion
Flow Distribution Fixture
Elutriating Leg
Condensate Out