Live online course – starts on 20 October 2020.
Join recognised expert Henry Kister online to learn how to get the best performance from a distillation column control system.
Through Henry's extensive experience, you will learn how to troubleshoot a distillation control system and identify causes of poor performance, evaluate existing column control performance, avoid common causes of instability, and develop improvements to your column control system. Henry will use case studies throughout to illustrate the principles and illustrate control systems that did not work.
Teaching will be delivered via two live modules (approximately three hours in length each) and will include Q&A sessions.
An e-certificate will be issued at the end of the course to confirm attendance and CPD hours logged.
By the end of this course you will understand how to:
- 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
Who will benefit
- engineers and operation personnel responsible for operating, troubleshooting, designing and revamping distillation columns in the chemical, petrochemical and oil refining industries
- process control engineers engaged in control system optimisation and improvements
- managers and supervisors endeavouring to get the best performance from an existing or new distillation unit
Distillation control overall schemes troubleshooting
Assembling control loops into an overall scheme: what works, what causes instability, and what impairs efficiency. The three 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 three 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?
Troublesome temperature controls and sidedraw controls
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 vapour? Best temperature control tray location: is there a reliable method that can find? Using simulations to search and find. 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. Analyser controls: is it the panacea for composition control? What has been the experience with an analyser control cascading onto a temperature control?
Pressure and condenser process controls troubleshooting
What makes good pressure control so critical? A vapour top product: how pockets in vapour lines destabilise 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 vapour bypasses: why some work while others don’t. Hot vapour bypass good and bad practices. Flooded reflux drums: pros and cons. Manipulating the coolant rate: when can it be troublesome? How manipulating the cooling water flow can accelerate fouling and corrosion. Liquid product with a small vapour 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.
Reboiler process controls troubleshooting
Reboilers heated by condensing steam or vapour: a control valve is 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 your condensate system can lead to instability and hammering. Equalising 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.
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 Henry and with other participants.
The following topics are outside the scope of this course and will not be covered: advanced controls of distillation columns, constraints controls, batch distillation controls, reactive distillation controls, controls of dividing wall columns, setting tuning constants, control valve selection, actuators, and control hardware.
Module dates and times
Tuesday 20 October 2020, 18:00–21:00 BST.
Thursday 22 October 2020, 18:00–21:00 BST.
Not available then? Register your interest in future course dates.
- IChemE member: £720 + VAT
- Non-member: £864 + VAT
Discounts are available to companies booking more than one place:
- 2 places–10% discount
- 3 places–15% discount
- 4 or more places–20% discount.
Bookings must be made at the same time to receive the discount.
Modules will be delivered via GoToWebinar®– check system requirements >>
You are advised to join the session at least ten minutes before the scheduled start time, to allow for your computer to connect.
This can also be delivered as a virtual in-company course. Contact us for more details.