‘My idols were always scientists’
- By Kanina Foss
An NRF B1 rated researcher who has been passionate about science since childhood has joined the School of Chemical and Metallurgical Engineering at Wits University, where he holds the NRF/DST Chair in Sustainable Process Engineering, bringing his intention to continue furthering a niche field which has important relevance to key national development priorities.
Professor Thokozani Majozi admits that the broad area of his research – process integration – is not new. In fact he did his PhD at the Centre for Process Integration at the University of Manchester Institute of Science and Technology where Pinch Technology (a proven, systematic methodology for saving energy) was first developed in the early 1980s.
But as the field of process integration has evolved, it has become clear that there are many critical areas which have not yet been covered. One of these is batch chemical process integration.
Batch operations are different to continuous operations in that they are time dependent. Cooking is a good example of a batch operation and if you have cooked, you have operated a batch reactor. The pots in your kitchen are batch reactors and every time you follow a recipe, there’s an element of time which is important to achieving the final product.
Continuous operations, by contrast, have the capacity to achieve steady-state, thereby rendering the time dimension irrelevant. If one takes a snapshot of a continuous unit operation at steady-state at two different points in time, one will see exactly the same thing. Consequently, these operations can be frozen in time, which entails many computational benefits in process integration.
Process integration, in the inception of the discipline, was meant for continuous operations. ‘It made sense at the time because continuous operations use a lot of energy and water whilst generating a lot of emissions. Over the years the discipline has evolved to embrace batch operations, which are mostly used in the manufacture of low volume, high value added products. These processes tend to be more complex and we don’t fully understand them yet,’ says Majozi.
Majozi’s research group is looking at three aspects of batch chemical process integration – sustainable optimisation, sustainable design and sustainable synthesis.
His book on batch chemical process integration was published by Springer in 2010, making it one of the first books on the topic. ‘When people start to publish books on a topic, it is an indication that they are only just starting to understand it. We are still in the very early stages. We have to work very hard,’ he says.
In the last five years, Majozi’s group has diversified a bit. In addition to batch operations, they are now looking at one specific aspect of continuous operations called utilities de-bottlenecking.
‘The hierarchy of process design begins with the reactor which is at the heart of the process. Then you think about separation because there is no reactor that has 100% conversion. After that you can think about the heat exchanger network – some operations could generate heat while others could absorb heat – and we think about how we could match the two to reduce the dependence on external utilities,’ says Majozi.
‘After you’ve exhausted that you think about external utilities like steam and cooling water. By utilities de-bottlenecking, we mean we want to design operations that are not as dependent on utilities. In South Africa, if you use more steam, you generate more carbon dioxide because we get most of our steam from coal.’
Majozi’s research is directly linked to broader national goals. ‘South Africa is going through a very difficult time in terms of energy. Although you hear Eskom saying – and I strongly believe in it – that individuals should switch off their lights, switch off their computers, truly speaking, the major users of energy are in the industrial sector. We should then find systematic ways to help industry use energy – and water – effectively.’
‘There has been strong interest from industry. We’ve already worked with Sappi, AECI, Johnson & Johnson and Sasol, and the pool of partners is increasing as we go along.’
Majozi started his professional career at Unilever in 1994. In 1996 he joined Dow AgroSciences and in 2002 he joined Sasol Technology as Technology Leader for Optimisation and Integration. He was appointed as an associate professor at the University of Pretoria in 2004 and promoted to a full professor at the end of 2008.
From 2005 to 2009, Majozi also held an associate professorship in computer science at the University of Pannonia in Hungary, spending four months of every year in Hungary.
He says this was one of the most beautiful experiences of his life. ‘It made me grow. I saw how different students could be. I found Hungarian students to be very proactive. If you’re a professor there, you know that you must be on top of your game at all times.’
As a result of his experience overseas, Majozi has made it a requirement for all his research students to spend time abroad. ‘None of my students finishes a degree without having spent some time overseas. There is nothing that untangles their minds like seeing what other people are doing. The biggest mistake we tend to make is that we confine them to one place and they begin to think that life begins here and ends here, which is very dangerous. It’s good for them to see talent elsewhere because when they come back, you can see the energy in them.’
He is committed to continuing teaching. ‘While my assignment at Wits – and my passion – is research, there is a proven case that research without teaching is incomplete, so I’ve requested some teaching duties. Teaching allows me to interact with students first hand and to identify best talent.’
Majozi is author and co-author of more than 100 scientific publications. He is a member of various scientific committees and organisations including the European Symposium on Computer Aided Process Engineering, the international Process Systems Engineering conference, and the Academy of Sciences of South Africa. He is a Fellow for the CSIR and the Academy of Engineering of SA.
He has received numerous awards for his research including the Zdenek Burianec Memorial Award (Italy, 2005), the National Science and Technology Forum Award for Distinguished researcher in the last five to 10 years (2006), the NRF President’s Award (P-rating, 2007), the NRF President’s Award (Transformation of the Scientific Cohort, 2008) and the University of Pretoria Leading Minds Award (2008).
In 2009, he was awarded the prestigious S2A3 British Association Medal (Silver). Recently, he received the South African Institution of Chemical Engineers Bill Neal-May Gold Medal (2010), the NSTF-BHP Billiton Award - Individual through Research and its Outputs (2011) and the AU-TWAS Award in Basic Sciences, Technology and Innovation (2012).
‘As a very young child, my idols were always scientists. I used to read the biographies of great scientists – Einstein, Dirac, Pascal – and this is still one of my favourite pastimes,’ says Majozi.
One of the reasons why he’s been able to translate his childhood dreams into such a successful career is a supportive wife and children. ‘My wife understands that I’m never in one place at any given time. Even my kids have grown accustomed to the fact that I might be in their vicinity but far away in terms of my thinking. I am sometimes there but not there. So they’ve been very supportive in their own way.’