MechChem Africa November 2019

⎪ Maintenance and asset management ⎪

as oxides, the hydrogen will strip the oxygen out of the oxide, forming water. At elevated temperatures, this is steam, and forms voids in the same way that methane does in steels, with the same effect on properties. The cure? Using oxygen-free copper alloys. There is a form of hydrogen problem I have never seen, but I’ve never worked in the nuclear fuel industry. It’s called ‘tritium bubbling’, where the hydrogen forms a fairly rare isotope called tritium (3H), which hap- penswhen the hydrogen in thematerial gains two extra neutrons in the nucleus when the material is exposed to a high neutron flux. The consequences are similar to those caused by hydrogen attack but it’s also radioactive. I hope you never see this problem either. Please note that the opinions expressed in this column are mine and mine alone. timjcarterconsulting@gmail.com

the atomic form on contact with iron at high temperatures. The hydrogen atoms enter the steel surface and react with the carbon pres- ent to formmethane, whichde-carburises the material and forms bubbles ormicro-fissures. Both the presence of micro-fissures and the decarburisation cause a significant loss of strength, resulting in major problems in high temperature, high pressure vessels contain- ing hydrogen, usually in the petrochemical industries. Unlikehydrogenembrittlement, hydrogen attack is irreversible, the only cure is replace- ment. It can be reduced, but not eliminated, by adding powerful carbide-forming alloying elements such as chromium or molybdenum. Hydrogen attack can also occur in copper alloys. And insilver, too. I have seen this incop- per conductors on an electric arc furnace. If thematerials, copper or silver, containoxygen

Apollo 13’s lunar landing was aborted after an oxygen tank in the service module failed two days into the mission. Courtesy: NASSA.

Maintenance critical to any responsible business Manyorganisations often see theprocess of pursuing maintenance as a must do rather than an opportunity. While the process of preserving maintenance regimes can often proof onerous, this does not have to be the case. South Africa’s engineering abilities remain world-class and delivering complex maintenance schedules can add value to any organisation and the community it operates in. and ensures that as much uncertainty in operating systems is minimal. This applies to machinery and devices such as valves, butmore importantly any humanoperators. “In our current economic climate, cost cutting and return on investment (ROI) have become top of mind. The fact remains that maintenance has tangible benefits and can impact the bottom line,” says Nqandela. Brimis Engineering is a company that spe- cialises in the fitment, maintenance and supply of valves, and has seen first-hand the necessity of risk-based maintenance of safety critical valves. The maintenance process needs to be carefully planned for each individual plant or system. According to Andile Nqandela, MD of Brimis Engineering, while this often includes staff training or planned maintenance, it also needs to ensure that maintenance looks beyond survival tactics Brimis Engineering, technical director: Moeketsi Mpotu says that the Internet of Things (IoT) has opened up massive po-

tential in the valves, piping and associated accessories maintenance sector. Working with skilled engineers who understand the industry and have a local professional perspectivemakespossibletheimplementa- tionof appropriate enabling technologies to ensure that the fourth industrial revolution doesn’t bypass the valve industry. Brimis Engineering is working towards providing remote access for clients to wit- ness valve testing and reduce any travel time for clients who usually attend testing. The valve test bench and lifting inspection divisionswill allow for remotewitnessing of certification and documenting of statutory calibration tests. Thiswill reduce travel time for theclient and thirdparty inspectors, over and above the secure cloud storage of test and calibration certificates. q

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