MechChem Africa December 2018

⎪ SAIChE IChemE news ⎪

backup, downcomer choking: Which one of these is limiting your tower capacity? The pros and cons of common tray types including sieve, moving valve, fixed valve and sheds: Which works well in fouling applications? Small holes and valves, the benefits and the traps. Flooding, what causes it, what affects it, how to predict it and are the predictions reliable? Are tray efficiency simulations andpredictions reli- able? Can the process be enhancedby tray modification? 4 Troubleshooting tray towers: Flooding and foaming symptoms: high differential pressures (dPs), reduced bottoms and others. Which can be trusted? Liquid and vapour sensitivity field tests: identifying the correct flooding mechanism. Tricks that will get you more information out of dPmeasurements. Gamma scans: applica- tions for diagnosing flooding, missing and damaged trays, foaming, and downcomer flooding. How to combine gamma scans with process checks to get the most out of the scans: the four keys to success. Do gamma scans ever lie? How to keep them truthful. 5 Troubleshooting packed towers: Rules of thumb for flooding pressure drop and packing efficiency. Simulation of hydraulic calculations: to trust or not to trust? Grid gamma scanning for detecting maldis- tribution, damage, distributor malfunc- tion, distributor and collector overflow. Distributor overflow: Death for packed beds! Somedosanddon’tsfordistributors. Can poor distributor feeding bottleneck towers? Circumferential surface tem- perature surveys: how to conduct them, what to avoid and the hidden secrets they reveal. 6 De-Bottlenecking: State-of-the-art trays and packings, strengths and weaknesses. Factors that favour trays and factors that favour packings. The pressure drop bonanza: why packings win in non-fouling vacuum services and in compressor suc- tion.Pitfallsuniquetostructuredpackings:

high pressure applications, oxidation, and shutdown fires. High-capacity trays such as Superfrac, VG Plus and MD: principles, tricks, and traps. Do they really give 30% more capacity than conventional equivalents? 7 Distillation control: Assembling control loops into an overall scheme; what works, which is better, what causes instability, and what impairs efficiency. The three most common causes of control assembly failure; no material balance control, fight- ing between temperature controllers, and level control on a small stream. Tips for avoiding problems: can controls affect revampsuccess?Besttemperaturecontrol locations: is there a reliable method for finding them? How can a temperature controller be fooled? Reboiler, condenser, and pressure controls: which loops work andwhichmisbehave.Howdeadpocketsin vapour overhead lines interfere with con- trols. Understandinghot vapour bypasses: why someworkwhileothersdon’t. Control systems that did not work. 8 Avoiding tower malfunctions: The 20 most common causes of distillation malfunctions: what trouble should we look for and prevent. Points of transition (feeds, draws, tower base): why these are some of the worst tower bottlenecks: how to diagnose these and remedy them. High tower base levels: how they induce premature flooding, even tray/packing damage and how you can prevent it. 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 oil or insoluble organics, other sources of tray damage and ways to avoid these. Some commissioning and startup issues: pre-startup inspection, blinding and unblinding, reverse flow, steam-water operation, washing, rapid pressuring/depressuring, drawing vac- uum, introducing liquid. Chimney trays: dos, don’ts and how they bottleneck tow- ers. Liquid outlets: choking in sidedraw

SAIChE IChemE SAIChE Board members: President: C Sheridan Imm. Past President D van Vuuren Honorary Treasurer L van Dyk + Vice President: Honorary Secretary: EMObwaka Vice President: D Lokhat Council member: JJ Scholtz Council member: AB Hlatshwayo Council member: K Harding Council Member: M Low Council Member: HMazema Council Member: MChetty Council Member: A de Bondt Council Member: MMabaso Council Member NN Coni Member (co-opted): MD Heydenrych Member (co-opted): MHughes Member (co-opted): CMausse Chair Gauteng: C Sandrock Chair KZN: D Lokhat Chair Western Cape: HMazema Contact details SAIChE PO Box 2125, North Riding, 2162 South Africa rundown lines and how it restricts tower capacity. Why must self-venting flow be assured in the presence of entrained vapour? Case Studies will be scattered throughout to illustrate the key principles and to distinguish good from bad practices. Delegates are also invited to bring along details of their applied distillation problems to share with others or one-on-one with Henry Kister. Course registration for the full three days includes Henry Kister’s textbooks and all course notes, teas, coffees, snacks and lunch. Please note that delegates are responsible for arranging their own accommodation. No provision for accommodation cost is made in the conference fee. All SAIChE IChemE members are eligible for a 10% discount, while companies sending more than 10 delegates will receive a 5% discount. courses@saiche.org.za

SAIChE IChemE member group news SAIChE IChemEWesternCape invited itsmembers to attend a talk byAnton Eberhard on ‘TheGlobal EnergyRevolution’, whichwas aSouthAfricanAcademyof EngineeringLecture. It was verywell attended by about 200 people. This very interesting and enlightening talk highlighted the importance of renewables and a distributed network. SAIChE IChemE KwaZulu-Natal members group held their AGMon the 30 November 2018. Theywould like toextend their thanks tomembers for their support andattendance. SAIChE IChemE is also very excited to announce that its SAIChE IChemE Congress 2020 will be held from July 1 to 3, 2020 at the University of the Witwatersrand in Johannesburg. To find out more about the event or the various structures of sponsoring the event, please contact the SAIChE IChemE office. saiche@mweb.co.za

Tel: +27 11 704 5915 Fax: +27 86 672 9430 email: saiche@mweb.co.za saiche@icheme.org website: www.saiche.co.za

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