The team for Afrox was headed by Thomas Riebe, project manager at LINDE PLANTSERV® and former commissioning lead for air separation units as well as project manager for adsorption plants. In addition to five experts from Linde Engineering India, three colleagues from Pullach provided on-site support at different times in the project. “Our partner in South Africa was very keen to see what a fresh pair of eyes might discover at the various sites,” explains Riebe. The project was given the symbolic name “Vula”, which means “open” in Zulu. The name was chosen to reflect the team's commitment to analyzing and assessing the plants without any preconceptions – and to discussing the results openly with the customer. The actual project comprised three tasks: updating the plants’ existing piping and instrumentation diagrams (P&ID), checking safety standards on site and then implementing suggestions for improvement to ensure safe, sustainable plant operations. The LINDE PLANTSERV® team tailors the actual health check process flow to the individual needs of each plant operator.
In the second phase, the Linde experts ran through incident scenarios on the drawing board. Here, they used “what if” questions to explore process safety, basing their work on the updated P&IDs. “We asked our Afrox colleagues a range of questions such as: What happens if the pressure or temperature in process components exceeds the design limits? Or what if other process parameters push plant components to their design limits and create safety-critical process conditions?” elaborates Riebe. If excess pressure builds up in the compressor, for example, the engineers were informed that either the existing safety valve releases the excess gas pressure or that the pipe downstream of the compressor outflow pipes was designed to handle a higher pressure than the compressor can deliver. This protects the plant and its components from mechanical damage and prevents unscheduled downtime. The Linde experts tracked the imaginary incident step by step in the P&IDs, taking a very close look at the existing safety features in the plant.
During the third and final phase, the team assesses and ranks the suggestions for improvement. It also plans the next steps, including assessing whether any further on-site support is required. “We have decided to extend our collaboration with Linde and Thomas Riebe,” explains Lwazi Mkhandabila, Head of Bulk and On-Site Plants at Afrox. “We are really impressed with the results – the outcomes have certainly exceeded all our expectations.” Riebe’s proposals identified significant optimization potential for the Witbank standby plant. Fine-tuning the expansion turbine in Pretoria reduced liquid nitrogen consumption by 27 tons a day without necessitating any changes to the operating conditions.
For Riebe, the Vula project demonstrates perfectly how LINDE PLANTSERV® is in synch with customer needs and how the resident engineers team up with plant operators on the ground to meet these needs in the most effective way possible. “Our goal was to ensure that Afrox could continue to operate its portfolio of assets in a safe, reliable and more efficient way. It was not about selling as many parts or revamps as possible,” adds Riebe. Afrox wanted Linde’s experts to assess the functionality, efficacy and safety of its plants – and not necessarily benchmark them against the latest cutting-edge technologies. Riebe's team remained focused on this philosophy throughout the entire Vula project. This was another reason why Afrox chose to continue working with the team. The figures given above are conclusive proof that the project was a resounding success. They also show that sound advice from LINDE PLANTSERV® cannot be expressed in terms of costs – it’s a valuable investment in future profitability.
