Distillation is one of the widely used separation method in most of the Chemical Process Industries. Improper design/ operation & maintenance leads to various troubles like reduced plant capacity, poor quality of separated products, high energy consumption, etc. This presentation is for learning about the troubleshooting of packed type distillation systems. Through conceptual aspects of the overall distillation system, reader can easily identify the various causes of probable troubles and will be able to suggest their remedial measures.

1. Troubleshooting of
Packed Distillation Column
Enhancing Visualization
Pankaj Khandelwal
Chief Konceptor
B.E.(Chemical), M.Tech.(Chemical), DBM
Koncept Learning Center (Pune)
klcenter@gmail.com

2. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
a.) Capacity (Feed Rate)
Expected : 100 m3/hr
Actual : 90 m3/hr

3. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
b.) Quality of Separated Products
Expected : 95 %v/v ‘A’
Actual : 94 %v/v ‘A’
Top Stream

4. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
c.) Steam (Energy) Consumption
Expected : 10 TPH
Actual : 11 TPH

5. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
d.) Material Wastage
Expected : Zero
Actual : 1 TPD

6. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
e.) Replacement of Internals
Expected : 2 years
Actual : 6 months

7. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles
f.) Plant Shutdown
Expected : Nil
Actual : 4 times/year

8. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
a.) Inaccurate Column Design
o Diameter
o Height

9. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
b.) Wrong Purchase
o MOC
o Packing Size/ Type

10. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
c.) Improper Fabrication
o Nozzle Location in column
o Improper Sealing in Tube Pass

11. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
d.) Poor Erection
o Column Perpendicularity
o Liquid Distributor Leveling
o Condensor Elevation

12. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
e.) Careless Pre-commissioning Checks
o Debris left in column
o Glass in SG/LG Missing
o Wrong Direction of Rotameter

13. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
f.) Inexperienced Startup
o Fast Initial Heating
o No cooling water in condensor
o Higher feed rate at the start

14. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
g.) Casual Normal Operation
o High reflux ratio (than specified)
o Low feed temperature
o Sub-cooled reflux

15. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble may be due to
h.) Careless Maintenance
o Damaging column packing
o Changed gasket material
o Relocating instrument

16. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Distillation
First (Lab) Observation
50%w/w Liquid converts to 70%w/w Vapor

17. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Distillation
Second (Process) Requirement
Heat Liquid by Direct Contact Vapors

18. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Distillation
Here the Imperfection Starts (Man Made) which leads to Trouble
Third (Plant) Provision
Space like Packing for Heat & Mass Transfer

19. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
a.) Cylindrical Vertical Vessel with Nozzles, Manholes, etc.
 Atmospheric
 Pressure
 Vacuum

20. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing
 To provide space for Liquid/ Vapor direct contact
 Simultaneous Heat & Mass Transfer
 More Contact & Less Pressure Drop

21. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing
First Generation (Raschig Ring, Berl Saddle)
1895 to the 1950s
simple shapes with closed surfaces, robust
and stable design, cost-effective production

22. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing Second Generation (Pall Ring, Intalox Saddle)
late 1950s to the early 1970s
surfaces with cutted windows and bent tongues,
improved area distribution lowering pressure
drop and enhancing capacity

23. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing
Third Generation (Net/Grid Structures, IMPT Ring)
late 1970s to the 1990s
framework structure, large free cross section,
low pressure drop, high efficiency

24. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing Fourth Generation (Raschig Super-Ring)
late 1990s until present
lower pressure drop and better mass transfer
efficiency

25. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
b.) Packing Latest

26. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
c.) Support Plate

27. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know About Packed Bed Column
d.) Liquid Distributor
1. Gravitational Types
i. Orifice Type
ii. Weir Type
2. Pressure Drop Types
i. Spray Nozzle Type
ii. Perforated Pipe Type

28. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know Distillation System
Feed Preheater
Reboiler
Distillation
Column
Bottom Product
Cooler
Top Product
Cooler
Condenser
A + B
A
B
Steam
Steam
Cooling Water
Cooling
Water
Cooling
Water
Feed
Top Vapors
Reflux
Top
Product
Bottom
Product

29. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know Distillation System
Feed Preheater
Reboiler
Distillation
Column
Bottom Product
Cooler
Top Product
Cooler
Condenser
A + B
A
B
Steam
Steam
Cooling Water
Cooling
Water
Cooling
Water
Feed
Top Vapors
Reflux
Top
Product
Bottom
Product
a.) Feeding
• Gravity/ Pump
• Pre-heating

30. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know Distillation System
Feed Preheater
Reboiler
Distillation
Column
Bottom Product
Cooler
Top Product
Cooler
Condenser
A + B
A
B
Steam
Steam
Cooling Water
Cooling
Water
Cooling
Water
Feed
Top Vapors
Reflux
Top
Product
Bottom
Product
b.) Vapor Condensation/ Reflux
• Condensor – Horizontal/Vertical
• Partial vs. Total Condensation
• Reflux – Gravity / Pump

31. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Know Distillation System
Feed Preheater
Reboiler
Distillation
Column
Bottom Product
Cooler
Top Product
Cooler
Condenser
A + B
A
B
Steam
Steam
Cooling Water
Cooling
Water
Cooling
Water
Feed
Top Vapors
Reflux
Top
Product
Bottom
Product
c.) Heat Supply
• Direct / Indirect
• Reboiler – Thermosiphon, Forced, Kettle

32. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Design of Distillation (Packed Column)
a.) Height of Packing
Theoretical Stages x HETP
Based on Feed Condition & Reflux Ratio
Based on Packing Type

33. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Design of Distillation (Packed Column)
b.) Material & Energy Balance
Overall Material Balance
A=10 t
B=90 t
T =100 t
A=9.99 t
B=0.01 t
T=10 t
A=0.01 t
B=99.99 t
T=90 t

34. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Design of Distillation (Packed Column)
b.) Material & Energy Balance
At Reflux Ratio = 4
Reflux Flow = 40 t
Vapor Flow = 50 t
A=10 t
B=90 t
T =100 t
A=9.99 t
B=0.01 t
T=10 t
A=0.01 t
B=99.99 t
T=90 t

35. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Design of Distillation (Packed Column)
b.) Material & Energy Balance
Energy Balance
•for Condensor Load
•for Reboiler Load
A=10 t
B=90 t
T =100 t
A=9.99 t
B=0.01 t
T=10 t
A=0.01 t
B=99.99 t
T=90 t

36. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Design of Distillation (Packed Column)
c.) Column Diameter
Tower Area = Vapor Mass Rate / Vapor Mass Velocity

37. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
A.) Feed
a.) Feed Flow Rate
a.1) Expected = 100 TPH Actual = 50 TPH
a.2) Expected = 100 TPH Actual = 150 TPH
Vapor / Liquid Load

38. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
A.) Feed
b.) Feed Composition
b.1) Expected : 10% w/w ‘A’ Actual : 5 % w/w ‘A’
b.2) Expected : 10% w/w ‘A’ Actual : 20 % w/w ‘A’
Change of Feed Nozzle

39. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
A.) Feed
c.) Feed Temperature/ Condition
c.1) Expected : 900C Liquid Actual : 600C Liquid
c.2) Expected : 900C Liquid Actual : 900C Vapor
Heat Load to Reboiler

40. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
B.) Reflux
a.) Flow Rate
a.1) Expected : 50 TPH Actual : 25 TPH
a.2) Expected : 50 TPH Actual : 100 TPH

41. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
B.) Reflux
b.) Temperature
b.1) Expected : 790C Actual : 500C

42. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
C.) Steam in Reboiler
a.) Flow Rate
b.) Pressure
c.) Quality : Dry, Wet, Superheated

43. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Variation Analysis (in Designed Column)
D.) Cooling Water
a.) Flow Rate
b.) Temperature

44. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble Identification
a.) By Operating Parameter Study
Pressure, Temperature, Composition at different locations
Bottom Pressure Expected : 2.5 kg/cm2(g) Actual : 2.6 kg/cm2(g)
Bottom Temperature Expected : 105oC Actual : 104oC
Bottom Composition Expected : 0.01%w/w ‘A’ Actual : 0.1%w/w ‘A’

45. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble Identification
b.) By Visual Inspection
During Operation : Flooding through SG/LG
On Column Opening : Choked Liquid Distributor

46. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Trouble Identification
c.) By Advanced Tools
•Simulation Models
•Gamma Scanning
•X-Ray Analysis
•Video Camera

47. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Typical Troubling Issues
a.) Flooding
b.) Channeling
c.) Entrainment

48. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles within Column
a.) Fluid Specific
•Scaled/ Fouled Packing
•Corroded Packing
•Foaming Liquid

49. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Troubles within Column
b.) Hardware Specific
•Packing : Size, Type, Broken/Damaged Packing
•Liquid Distributor : Choked holes, Tilted, Under/Over sized
•Vapor Supply : Sheath

50. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Other Hardware Affecting Distillation
a.) Equipment other than Distillation Column
a.1) Heat Exchanger
•Feed Pre-heater
•Condensor
•Reboiler
•Coolers
•Heat Transfer Area – Less / More
•Orientation – Horizontal / Vertical
•Location - Elevation

51. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Other Hardware Affecting Distillation
a.) Equipment other than Distillation Column
a.2) Pump
•Feed Pump
•Reflux Pump
•Product Draw Pump
•Flow Rate vs. Head
•NPSH (Required) vs. NPSH (Available)

52. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Other Hardware Affecting Distillation
b.) Pipe Line
•Reflux Line with Loop
•Thermo-siphon Reboiler Piping
•Utility Piping – Steam, Cooling Water
•Vacuum Line
•Pump Suction Line

53. klcenter@gmail.comKoncept Learning Center
Troubleshooting of
Distillation Column
(Packed Type)
Enhancing Visualization
Other Hardware Affecting Distillation
c.) Instrument
•Wrong Calibration
•Control Valve Operation
•Wrong Placement/Installation

54. Koncept Learning Center
9371121220 klcenter@gmail.com
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9623232500
9371121220
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Enhancing Visualization
Since 2001