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Distillation Troubleshooting-2019

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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 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.

Publié dans : Formation
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Distillation Troubleshooting-2019

  1. 1. Troubleshooting of Distillation Pankaj Khandelwal Chief Konceptor B.E.(Chemical), M.Tech.(Chemical), DBM Koncept Learning Center (Pune) klcenter@gmail.com Enhancing Visualization
  2. 2. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Major Trouble of Distillation High Energy Consumption (for desired separation)
  3. 3. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Why the Trouble occur? First Observation 50%w/w Liquid converts to 70%w/w Vapor Second Requirement Heat Liquid by Direct Contact Vapors Third Provision Space like Tray/ Packing for Heat & Mass Transfer Here the Imperfection Starts (Man Made) which leads to Trouble
  4. 4. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Existing (Present) Trouble Financial Losses (Material, Energy, Time) Other Sides of Trouble “-” Side : Safety (If trouble is not solved) “+” Side : Plant Improvement All are easily possible by Visualization
  5. 5. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Enhanced Visualization by Advanced Tools  Simulation Models  Gamma Scanning  X-Ray Analysis  Video Camera
  6. 6. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Troubleshooter Tasks a) Identify the Trouble b) Determine its Cause c) Recommend a Remedy
  7. 7. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Major Distillation Problems arise from: a) Flooding b) Excessive Pressure Drop c) Inefficiency
  8. 8. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Major Troubles a) Low Plant Capacity b) Poor Quality of Separated Products c) High Consumption of Utilities d) Poor Efficiency/ Recovery e) Frequent Shut Downs
  9. 9. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Trouble Identification By CEO (Source Annual Report) Production Capacity Expected : 100 TPA Actual : 90 TPA Shortfall : 10 TPA WHY?
  10. 10. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Trouble Identification By Site Head (Source Plant Section Data) Section Expected Actual Reaction 10 TPD 10 TPD Filtration 10 TPD 10 TPD Drying 15 TPD 15 TPD Pulverizing 20 TPD 20 TPD Distillation 100 TPD 90 TPD Scrubbing 2 TPD 2 TPD
  11. 11. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Trouble Identification By Unit In-charge (Source Plant Section Data) Sub-Section Expected Actual Feed 50 m3/hr 45 m3/hr Top 50 TR 50 TR Bottom 35 TPD 35 TPD
  12. 12. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Trouble Identification By Section Engineer (Source Vendor Details) Pump Specification Flow Rate : 50 m3/hr Diff. Head : 20 MWC Actual Head : 21 MWC
  13. 13. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Trouble Identification By Design Engineer (Source Basic Calculation) Line Size Provided : 6” Required : 8”
  14. 14. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance a.) Fluid Flow Related b.) Heat Transfer Related c.) Mass Transfer Related
  15. 15. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance a.) Fluid Flow Related •Fluid Flows from “High Energy” to “Low Energy” Naturally •Otherwise add Energy by Pump
  16. 16. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance a.) Fluid Flow Related •External Flow Streams •Feed to Pre-heater •Pre-heater to Column •Steam to Pre-heater •Vapors to Condensor •Reflux to Column •Top Product to Storage
  17. 17. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance a.) Fluid Flow Related •External Flow Streams •Typical Troubles •Insufficient Liquid in Reflux Drum •Low Elevation of Gravity Feed Tank •High Pressure Drop in Reflux Line •Lower Head Pump Selected
  18. 18. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance a.) Fluid Flow Related •Internally, within Distillation Column •Typical Troubles •Liquid Distribution/ Redistribution in Packed Column •Slope in Trays •Higher Liquid Level in Downcomer
  19. 19. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance b.) Heat Transfer Related •Heat Naturally Flows from “High” to “Low” Temperature Q = U A ΔT
  20. 20. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance b.) Heat Transfer Related •Units Involved •Feed Pre-heater •Reboiler •Condensor •Top Product Cooler •Bottom Product Cooler
  21. 21. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance b.) Heat Transfer Related Q = U A ΔT •Typical Troubles Design Considered During Operation Heat Transfer Coefficient Low Reduced due to scale Heat Transfer Area Less Tubes Plugged Tubes Temperature Difference Less steam temperature or high cooling water temp. Low steam pressure or Cooling Tower Performance
  22. 22. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance b.) Heat Transfer Related •Other Troubles •Trapped Air in Steam (Reboiler) •Superheated Steam •Insulation Stripped Off
  23. 23. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance c.) Mass Transfer Related •Difference in Vapor & Liquid Composition as per Equilibrium
  24. 24. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance c.) Mass Transfer Related •Typical Troubles of Packed Column •Dry Packing – Less Liquid in Column •Flooded Packing – More Liquid in Column •Bigger Packing Size – Less available area for contact
  25. 25. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance c.) Mass Transfer Related •Typical Troubles of Tray Column •Less Liquid Level in Tray – Less vapor liquid contact •Missing Downcomer – Bypassing vapor to next tray
  26. 26. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Basic Issues Affecting Distillation Performance c.) Mass Transfer Related •Other Issues •Flooding •Entrainment •Weeping •Dumping •Channeling •Coning •Priming
  27. 27. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Fluid Specific Troubles of Distillation • Liquid with Suspended Solids • Liquid with Dissolved Solids • Liquid with Trapped Gases • Foaming Liquids • Corrosive Liquids • Decomposing Components • Flammable Liquids • Hazardous Liquids
  28. 28. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Column Internals Tray Column Outlet Weir Height : Low / High Inlet Weir Height : Low / High Down comer Height : Low / High Number of Sieves : Less / More Down comer Area : Less / More
  29. 29. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Column Internals Tray Column Wrong Location of Feed Nozzle (In down comer) Wrong Location of Side Stream Draw (in Vapor zone) Gap between Tray & Shell Valve tray vibration Improper slope of trays
  30. 30. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Column Internals Packed Column Packing Size : Smaller / Bigger Liquid Distributor : Plugging & Fouling Support Plate : Choked by Packing Inlets/ Outlets : Flashing fluids feed
  31. 31. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Column Internals Packed Column Fouled Packing Damaged Packing Improper Feed Introduction Flooded Gas Riser Excessive Entrainment Vapor Mal-distribution
  32. 32. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Heat Exchangers •Feed Pre-heater •Condensor •Reboiler •Coolers •Heat Transfer Area – Less / More •Orientation – Horizontal / Vertical •Location - Elevation
  33. 33. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Pumps •Feed Pump •Reflux Pump •Product Draw Pump •Flow Rate vs. Head •NPSH (Required) vs. NPSH (Available)
  34. 34. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Hardware Specific Troubles of Distillation Piping •Reflux Line with Loop •Thermo-siphon Reboiler Piping •Utility Piping – Steam, Cooling Water •Vacuum Line •Pump Suction Line
  35. 35. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Process Design High Design Margin in Capacity •Oversized Distillation column •Higher number of sieves
  36. 36. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Mechanical Design Wrong Location of Draw Nozzle
  37. 37. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Procurement Wrong Purchase of Packing Material
  38. 38. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Shop Fabrication Gap between Tray & Column Shell
  39. 39. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Site Fabrication Loop in Reflux Line wrongly located
  40. 40. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Erection Condensor at lower elevation
  41. 41. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Manpower Specific Troubles of Distillation Maintenance Down Comer not placed after Column Cleaning
  42. 42. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Troubleshooting to De-Bottlenecking Reflux Ratio Desired : 4 Actual : 3 Result : Poor Quality Product or Low Plant Capacity Reflux Ratio Operating : 4 Possibility : 3 Conclusion : for same product quality & quantity, lowering reflux reduces Energy Consumption.
  43. 43. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization Troubleshooter Skills 1. Safety first. 2. Good trouble shooters understand the basics well. 3. Know what to expect before you start. 4. Do not overlook the obvious. 5. The so-called mental model both helps and hurts the troubleshooting process. 6. Think of ways to challenge the mental model. 7. Testing strategy advice varies considerably, and depends on your situation. 8. Believe your instruments, unless you have a good reason not to. 9. Use people as sources of information.
  44. 44. klcenter@gmail.comKoncept Learning Center Troubleshooting of Distillation Enhancing Visualization
  45. 45. Koncept Learning Center 9371121220 klcenter@gmail.com 8237829150 9623232500 9371121220 www.facebook.com/KonceptLearningCenter www.konceptlearningcenter.com www.linkedin.com/company/koncept-learning-center Enhancing Visualization Since 2001

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