ACS219 Process Control Group assignment Payam Soulatiantork October 2023 1 Introduction The assignment is linked to chemical engineering applications related to control scheme design, instru- mentation, control strategies and looking

at the control of selected systems. Students work in groups of four students to produce a number of separate posters, one for each case study. The main purpose of each poster is to demonstrate the importance of a given control strategy or design in the context of chemical engineering. The poster should include context and numerical illustrations and, for high marks, should also include evidence of analysis and independent systematic design. A typical case study could either: (i) focus on the efficacy of different strategies for controlling a given system, or (ii) the efficacy of a given strategy for tackling particular scenarios, perhaps using several systems to illustrate. Most likely numerical evidence will be produced using Matlab or TSC although other software tools may be used. This is 45hr work per student and thus to achieve good marks, the submissions must not be superficial. Typical marking guidance is provided at the end for information. As this is a group work assignment, each group will also need to submit, as a group, an agreed peer assessment of the contribution of each group member with some explanation and evidence where the marks are not awarded equally. In order to ensure no group member is disadvantaged or excluded, groups will have a private discussion board on Blackboard they can use to communicate dates, locations and summaries of core meetings as well as to share interim documentation. The groups are self-enrolled so you can choose the students you want to work with on your project. Some possible scenarios are listed over the page, but students should feel free to explore other areas they find interesting which fall within the remit. Some good resources including some Matlab files are also available on the BB page -> Group assignment for ACS219 -> Coursework useful material. • Students are reminded that the substantive work submitted should be their own. Where resources have been used from elsewhere, these must be clearly and explicitly referenced. • Students are reminded of University policy on unfair means and moreover should ensure that any resource they use is fully cited. http://www.shef.ac.uk/ssid/exams/plagiarism. • Groups can meet with staff during the tutorials and lectures to discuss any queries. Please see staff immediately if special circumstances are affecting your performance http://www.shef.ac.uk/ ssid/forms/special. Group feedback will appear on Blackboard after marking is complete for the whole class. 2 Submission details Posters are submitted in soft copy onto Blackboard through the group assignment link. The deadline is the Friday of week 12 of semester 1, 15 December 2023 at 5pm. 3 Feedback Group feedback will appear on Blackboard after marking is complete for the whole class. Also, in a single hour lecture on Friday of week 11, the students will get a chance to bring their posters along and get some interim feedback. 1 4 A table of potential themes Case study scenario Low order systems for use in the case studies Systems in series and higher order dynamics Multi-input-multi- output systems Impact of constraints and actuation choices Impact of measurement and delays Advanced control strate- Develop an awareness of some alternative control strategies and why these gies are deployed in industry such as: cascade, feedforward, selective control, split-range control, ratio control, model predictive control, smith predictors and time delays, anti-windup strategies, inferential control, fault-tolerant control, optimal control, robust control, sequence control, on-off control. Discrete control Fault tolerant con- trol/safety Impact of design on con- trol performance Impact of uncertainty PID tuning Possible content 1st order in series, distillation column, multi-tank system, thermocouple delay, power generation, stirred tank with cascade. Valve sizing Higher order systems are less easy to control with PI. Students can explore through several case studies the consequences of more involved dynamics such as multi-1st-order in series, non-min phase. (Multi CSTR, multi-tank, distillation column, etc.) Discuss the challenges of controlling systems with interacting dynamics. Illustrate with case studies such as distillation columns and oil fired power generation. Use case study examples to demonstrate how constraints limit performance and impact on safety. Brief discussion of how these might be handled in practice (say with PID and predictive control). Use case studies to analysis the impact of actuator choices on controllability, constraint handling and performance. Consider the consequences on control performance (and safety) of poor measurement such as accuracy, repeatability, lag/delay, reliability. Use a few case studies illustrating different sensor choices to show how these impact on control loop performance. Include inferential control. What is the impact of discretising a control law that is implementing via a computer and thus involving sampling? Use some case studies to demonstrate the impact of actuator/sensor failure and discuss possible mitigation. Show through case studies how poor design effects control, e.g. Vaporizer, reboiler, knockout drums, ball mills, cooling towers, simple distillation tower, etc. How would you undertake control design when the system/model parame- ters are continually changing, or unknown? What is the impact on control of significant sensor noise or large input/output disturbances? Compare and contrast different tuning methods for PID, e.g.: Zeigler- Nichols, Cohen-Coon, Modified Ziegler-Nichols method, Tyreus-Luyben method, Damped oscillation method, C-H-R method, Fertik method, Ciancone-Marline method, Minimum error criteria (IAE, ISE, ITAE), etc. Identify, select and position different instruments appropriately within a control loop. 2 5 Marking criteria and Grade Descriptors for ACS219 group assignment 7-10 • Extensive knowledge of the subject area and the engineering context. A perceptive and focused use of the relevant material. Widespread evidence of independent sourcing and original thought. 5-6 6-7 • A sound knowledge of the subject area and engineering context. A comprehensive use of the relevant material with some evidence of independent sourcing and original thought. 4-5 • Shows an insight and depth of understanding, including an awareness of the complexities and subtleties. 3-4 ● Very high standard of critical analysis and evaluation. • Clearly structured presentation, showing logical development of arguments and properly referenced data and examples. • Shows an understanding of arguments, contribution and context, including some awareness of the complexities and subtleties. ● High standard of critical analysis of the source material. Evidence of some evaluation and synthesis. • Clearly structured presentation, showing logical development of arguments and properly referenced data and examples. • Some knowledge of the subject area and engineering context. Makes some use of the relevant material with little or no evidence of independent sourcing, or original thought. • Shows some understanding of arguments, contribution and context. • Attempts analysis of the source material but may include some errors/omissions. Little evidence of evaluation and synthesis. • Presentation reasonably clear with arguments not fully developed and data and examples not fully referenced. • Some knowledge and appreciation of the engineering context. Superficial use of the material provided. No evidence of independent sourcing, or original thought. • Some areas of understanding of the arguments, contribution and context. • Confused analysis including errors and omissions. No evidence of evaluation and synthesis. • Descriptive presentation based on confused arguments. Includes poorly referenced data and examples provided during lectures. • Limited and patchy knowledge and appreciation of the engineering context. Poor use of the material provided. No evidence of independent sourcing, or original thought. • Limited understanding of the arguments. No understanding of the contribution and context. • Confused analysis including a number errors and omissions. No evidence of evaluation and synthesis. • Descriptive presentation based on confused arguments. Poor use of data and examples provided during the lecture. No references 0-3 ● Inadequate knowledge and no appreciation of the engineering context. Poor use of the material provided. No evidence of independent sourcing, or original thought. 3 ● Inadequate understanding of the arguments, contribution and context. • Inadequate grasp of the analysis including many errors and omissions. No evidence of evaluation and synthesis. • Presentation that contains no data, examples or even class notes. 4