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Practical Distillation Technology 
3 Day Troubleshooting Program - Chemical Towers

Now Offering In Person Courses

About the Course

INTRODUCTION
  • This down-to-earth course gives comprehensive coverage of distillation technology, with particular emphasis on the problems that can occur and how to solve them. 

  • It provides an excellent opportunity to develop a working knowledge of key techniques that can promote trouble-free operation and reduce distillation cost.

 

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WHO SHOULD ATTEND
  • Engineering and supervisory personnel who are involved in -

    • Operating

    • Troubleshooting

    • De-bottlenecking

    • Designing

    • Starting up of distillation processes​

YOU WILL LEARN HOW TO
  • Troubleshoot a distillation column and determine what may cause poor performance

  • Evaluate existing column performance and develop new designs

  • Avoid common causes of capacity bottlenecks, tray damage, downcomer unsealing problems, packed tower distributor malfunctions and many other operating difficulties

  • De-bottleneck a column to improve capacity and/or separation

  • Control and operate a distillation column

  • Validate your tower simulation

CASE STUDIES
  • Case studies will be scattered throughout, brought in to illustrate the principles

AFTER-HOURS INFORMAL SESSION
  • This optional session, which will be held following the program on day one, is an opportunity to discuss items that are not on the formal program and take longer to discuss.

  • Participants are encouraged to bring materials in a form that can be projected on the screen so that everyone in the audience can view and discuss.

  • Participants are also encouraged to bring with them backup material (tray and tower drawings, gamma scans), as often innocent-looking details turn to be major issues.

Course Program

Day One

Day Two

TROUBLESHOOTING TRAY TOWERS

  • Flooding and foaming symptoms: high dP’s, reduced bottoms, others. Which can be trusted?

  • Liquid and vapor sensitivity field tests: identifying the likely flood mechanism.

  • dP plots: getting the most of your plant data to diagnose floods.

  • Foams: common causes, diagnoses, and dealing with them.

  • Gamma scans: application for diagnosing flood, missing and damaged trays, foaming, and downcomer flooding.

  • How to combine gamma scans with process checks to get the most out of the scans and avoid misinterpretation: the four keys to success.

PACKINGS HYDRAULIC LIMITS  

  • Random and structured packing generations: how much improvement do the “best and latest” offer over their predecessors?

  • Which packings do better in fouling or polymerizing environments?

  • Visualization of normal and flooded packing operation.

  • Rules of thumb for flood pressure drop and packing efficiency.

  • Simulation hydraulic calculation: to trust or not to trust?

         

TROUBLESHOOTING PACKED TOWERS

 

  • Why is good distribution critical for packed towers

  • Common distributor types: which one handles fouling better?

  • Grid gamma scanning for detecting maldistribution, damage, distributor malfunction, distributor and collector overflows.

  • Distributor, collector, and parting box overflows: DEATH for packed beds. How to diagnose and how to avoid.

  • Some do’s and don’ts for distributors. Can poor distributor feeding bottleneck towers?

  • Temperature surveys: application for simulation and maldistribution checks. How to conduct, what to avoid, and the hidden secrets they reveal.

  • Neutron backscatter and CAT scans: what can they reveal that regular gamma scans cannot.

 

DEBOTTLENECKING

  • State-of-the-art trays & packings: strengths and weaknesses.

  • Factors that favor trays and factors that favor packings.

  • The pressure drop bonanza: why packings win in non-fouling vacuum services, in compressor suction and in the path of a fan.

  • Pitfalls unique to structured packings: high pressure application, oxidation, shutdown fires.

  • High-capacity trays (e.g. Superfrac®, VG Plus®, MD®, Hi-Fi®): principles, tricks, and traps. Do they really give 30% more capacity than conventionals?

Day Three

DISTILLATION CONTROL

  • Assembling control loops into an overall scheme: what works, what causes instability, and what impairs efficiency.

  • The 3 most common causes of control assembly failure: no material balance control, fighting between temperature controllers, and level control on a small stream. Tips for avoiding problems.

  • Challenges in controlling a column with a side draw and how overcome.

  • Special considerations for azeotropic and extractive distillation controls

  • Best temperature control location: is there a reliable method that can find it? 

  • Condenser, and pressure controls: which loops work and which misbehave.

  • How dead pockets in vapor overhead lines interfere with controls.

  • Flooded condenser controls: what are their pitfalls and how avoided.

  • Can controlling the coolant be troublesome?

  • Can coolant control interfere with vacuum control?

  • Reboiler control: Does it make a difference if the control valve is in the steam or condensate?

  • Impact of valve location on energy efficiency, reboiler fouling and corrosion, loss of reboiler seal, hammering, reboiler stall, and tube leaks.

  • Control systems that did not work.

         

IDENTIFYING AND REMOVING POTENTIAL TOWER MALFUNCTIONS

  • What malfunctions should troubleshooters look for? Do the malfunctions repeat themselves? How can these malfunctions be alleviated?

  • Points of transition (feeds, side draws, tower base): why these are some of the most severe tower bottlenecks.

  • Drawing sketches (to scale) to troubleshoot these internals: you need a sketch, not an expert.

  • High tower base levels: how they induce premature flood, tray/packing damage, tower overfills, and how to prevent.

  • Common instrument issues at the tower base: what to watch out for.

  • Tray/packing damage: pressure surges due to water entering a tower full of hot insoluble organics, other sources of tray damage and ways to avoid.

  • Examining operation charts: what happened first?

  • Common accumulator tray problems: overflow, hydraulic gradients, liquid bypassing.

  • Liquid outlets: choking in sidedraw rundown lines and how it restricts fractionator capacity.

  • Kettle reboilers: why are they common causes of bottlenecks.

AVOIDING FRACTIONATION PITFALLS

  • Vapor-liquid equilibrium (VLE): key concepts and simulation traps. Should we believe the simulation?

  • Issues with close-boilers and non-idealities: why some heavy components go up while the simulation thinks they go down.

  • Chemical reactions in towers: how to test for.

  • VLE data: to trust or not to trust?

  • Multi-component distillation: composition profiles, sidedraws, accumulation, and cycling problems. Things to watch out for.

         

TROUBLESHOOTING DISTILLATION SIMULATIONS       

  • Does your simulation reflect the real world? How poor simulation leads to incorrect problem diagnosis. What validation checks are needed? How far should we go?

  • Temperature profiles: application for simulation validation and for identifying a second liquid phase.

  • Sensitivity analysis and graphics for simulation troubleshooting: useful hints.

 

TRAY HYDRAULICS & LIMITS

  • Visualization of vapor-liquid dispersions on trays, flooding, entrainment, weeping, dumping. 

  • Flood mechanisms: jet (entrainment), system limit, downcomer backup, downcomer choke. Which one is likely to limit your tower capacity?

  • Common tray types: sieve, moving valve, fixed valve, sheds: pros and cons. Which works well in fouling applications?

  • Small holes, valves: benefits and traps.

  • Hole area: can too much lead to troubleshooting assignments?

  • Flood: what causes it, what affects it, and how predicted. Are the predictions reliable?

  • Tray efficiency: are simulation predictions reliable? Can efficiency be enhanced by tray modification?

  • Scale up from bench scale towers: how reliable?

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