Chemical Technology March 2015

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Contents

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Regular features 3 Comment

Control & instrumentation 14 Functional safety for machine controls

When implementing technical protective measures from the ‘hierarchy of controls’, each risk reduction measure will be associated with a safety function or combination of safety functions. For these safety functions to be designed and installed to a degree of reliability commensurate with the risk level of the associated hazard(s), the concepts of functional safety must be applied. by SICK Safety Application Specialist, Chris Soranno Nanotechnology 22 Self-cleaning surfaces have widespread applications A surface that is hydrophobic has an astonishing number of properties. Besides the obvious one of water pouring off, bacteria, fungi, algae and other pathogens cannot get a grip either. The difficulty in creating synthetic surfaces with similar properties is that they are damaged over time. by Gavin Chait 20 Focus on control & instrumentation

35 IChemE SAIChE news 36 Sudoku 103/Et cetera Cover story 4 New generation of encapsulated disc spring system from AESSEAL AESSEAL recently launched LiveStar, a new-generation live- loading system, designed to be compact without requiring extra bolt length to accommodate the uncompressed disc spring stack – a system which will find a major market in control valves in environmentally sensitive applications. Corrosion & coatings 6 Corrosion problems in incinerators and biomass-fuel- fired boilers Incinerators are widely used to burn municipal waste, biowaste, wood, straw, and biomedical waste. Combustion of these wastes results in the generation of chlorides of sodium and potassium which may attack the metallic part of the incinerator. In biofuel- fired boilers, a similar type of highly corrosive environment is also found. by Deepa Mudgal, Surendra Singh, and Satya Prakash, all of the Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee, Uttarakhand, India

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Chemical Technology is endorsed by The South African Institution of Chemical Engineers

25 Focus on nanotechnology

Supply chain management 26 Profitability through supply chain excellence −

A ‘Technology Insight’ for specialty chemicals producers Globalisation and the uncertainties of an ever-changing economic landscape have introduced new complexity to the specialty chemicals business. On a daily basis, specialty chemicals producers must navigate multiple variables to determine the most profitable products to produce, when and where to produce them and how to successfully execute against that plan. Article supplied by IChemE and Aspentech

11 Focus on corrosion & coatings

and the Southern African Association of Energy Efficiency

DISCLAIMER The views expressed in this journal are not neces- sarily those of the editor or the publisher. Generic images courtesy of www.shutterstock.com

33 Focus on supply chain management