Online Courses

Course Delivery

The Online Troubleshooting Distillation Controls Course is a live two day course given virtually.

This course is designed for groups and can be given via platforms such as Microsoft Teams, Zoom, etc.

Troubleshooting Distillation Controls

Engineers and operation personnel having responsibility operating, troubleshooting, designing, and revamping distillation columns in the chemical, petrochemical, and oil refining industries
Process control engineers engaged in control system optimization and improvements
Managers and supervisors endeavoring to get the best performance from an existing or new distillation unit

Troubleshoot a distillation control system and identify causes of poor performance
Evaluate existing column control performance and develop new designs
Avoid common causes of instability, off-spec products, excessive energy consumption, hammering, fouling, and other operating issues resulting from deficiencies in the control system
Incorporate lessons from past experience for developing or improving a column control system

Control systems that did not work case studies will be scattered throughout, brought in to illustrate the principles

These are primarily intended to answer questions on the presentation.
However, if time permits, these sessions may provide an opportunity to briefly discuss plant issues with the instructor and with other participants.
- Participants who wish to discuss plant issues should prepare simplified presentation materials so that viewers can easily follow. Include information on connecting lines to drums and seal pots (enter from top or bottom, via slotted pipes or bare nozzles, into the vapor or liquid space, etc.).

Advanced controls of distillation columns, constraints controls, batch distillation controls, reactive distillation controls, and controls of dividing wall columns are outside the scope of this course.
Setting tuning constants, control valve selection, actuators, and control hardware are also outside the scope of this course.

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. What may happen in the absence of adequate material balance control?
The 3 most common column control schemes: pros and cons. Is it better to connect the column temperature (or composition) control to the boilup or to the reflux? Is there a control scheme that can handle ambient disturbances better?
What can go wrong with controlling a liquid level on a small stream? What makes violation of this principle the No. 1 control problem in refineries (and in many chemical plants). Is your fractionator immune?

How does subcooling affect internal reflux flow rate and its control? Is internal reflux control useful?
Why distillation control schemes often break down in the presence of a side draw and what can be done to make them work. Can internal reflux control help?
Temperature control: is it better to have the control thermocouple in the liquid or in the vapor?
Best temperature control tray location: is there a reliable method that can find it? Using simulations to search and find it.
Application to several case studies: what does this method reveal about the tower in each case, and how it can guide the solutions. What is the effect of non-key components?
Issues with enhanced distillation column controls: azeotropic distillation and extractive distillation, and what has achieved success in controlling them.
Analyzer controls: is it the panacea for composition control? What has been the experience with an analyzer control cascading onto a temperature control?

What makes good pressure control so critical?
A vapor top product: how pockets in vapor lines destabilize pressure controls.
Flooded condenser pressure controls for total condensers: how can the piping connections to the reflux drum make or break the control stability.
Why can flooded condenser pressure controls break down in the presence of non-condensables, undersized equalizing lines, slots in the dip pipe entering the reflux drum, and what can help avoid these issues. Does inert padding help, and at what cost?
Understanding hot vapor bypasses: why some work while others don’t. Hot vapor bypass good and bad practices.
Flooded reflux drums: pros and cons.
Manipulating the cooling water flow: how it can accelerate fouling and corrosion. When is recycling warm cooling water helpful?
Liquid product with a small vapor vent stream: why controlling the cooling water may sometimes be unavoidable, and what can be done to overcome shortcomings.
Interference between vacuum and coolant controls.
Coolant controls for air condensers and refrigerated condensers.

Reboilers heated by condensing steam or vapor: a control valve in the steam inlet line versus valve in the condensate outlet line. Is the dynamic response with the steam inlet valve always better?
Reboiler seal loss with the condensate outlet valve and how avoided.
When does the condensate outlet valve scheme have a major energy-efficiency advantage?
Fouling, corrosion, and thermal stresses: which of the schemes can handle each of these issues better?
Steam trap unreliability issues with the steam inlet valve scheme: how to overcome.
Startup and low rate operation with the steam inlet valve scheme: reboiler “stall”, instability, how to prevent.
Hammering: how a scheme incompatible with the condensate system can lead to instability and hammering.
Equalizing lines to the condensate pot: checking out for poor configurations that can induce instability, hammering.
Tube leaks: which scheme is better suited to handle a potential tube leak in different circumstances?
Reboilers heated by sensible heat: why are the controls of these far less troublesome, and a brief discussion of their few issues.