A sizeable proportion of the processes and equipment at Chemelot are to be powered by sustainable electricity by 2050 in order to considerably reduce overall CO2 emissions. Plasma technology has the potential to electrify chemical processes, making it one of the options being explored by Brightsite within its ‘Emission reduction through electrification’ programme line. Support from the NXTGEN Hightech project is enabling Brightsite to work towards the next step, which entails actually using plasma technology on an industrial scale.
“Plasma technology is a ‘game changer’ when it comes to the electrification of processes in the chemical industry (see box ‘What is plasma technology?’)”, says Hans Linden, Programme Manager at Brightsite. “Plasma technology, using electricity generated from sustainable energy sources, is enabling us to convert methane to hydrogen and high-quality hydrocarbons such as acetylene and ethylene, the basis for plastics, without releasing CO2. There’s no combustion process and no oxygen is used; all the methane gets used to create carbonaceous products and hydrogen. The results of the research from Brightsite’s plasma lab are promising, but before we can operate on an industrial scale the process needs to be developed and the equipment needs to be available to incorporate plasma technology into the factory processes. We’re delighted that the subsidy obtained from the NXTGEN Hightech project, part of the Growth Fund, made it possible for us to take the next step through this project geared towards concretising industrial use of plasma technology”, says Linden.
The NXTGEN project team working on plasma equipment development. From left to right Yves Creyghton, Hans Linden, Thomas Butterworth (not in photo Hans Kroon).
What is required for the scale-up?
“Plenty of things have to be done prior to large-scale use of plasma technology in industry being possible. Machinery has to be developed to build industrial equipment, for instance. Such machinery doesn’t yet exist, as there aren’t yet many factories in which plasma technology is the driving force. And so plasma equipment development is key within the NXTGEN project. To this end, we need to ascertain the ideal scale for a plasma module, perhaps having several of them consecutively”, says Linden.
“As a matter of fact, we’ll have to work out what system size is suited to converting methane to valuable hydrocarbons. That will entail us considering the methane conversion rate and the acetylene and hydrogen yield per unit, the type of plasma source, the connection to the electricity grid and the equipment costs. Taking all factors into account will allow us to come up with a single design in the end. The puzzle is likely to be solved slightly differently for plasma processes other than acetylene and hydrogen formation and the optimum will probably be different”, expects Yves Creyghton, Plasma System Engineer at TNO.
Yves Creyghton, Plasma System Engineer at TNO:
“We need to turn the knowledge that we’re gaining as a team into something useful for the parties who will ultimately be the ones producing the equipment.”
Joint project in uncharted territory
Brightsite partners UM, TNO and Sitech Services constitute the crux of this NXTGEN Hightech plasma project and Brightsite Plasma Lab (see box ‘Brightsite Plasma Lab’) is the place where it is being implemented. “This project is challenging; scaling plasma technology up to an industrial scale is pretty much uncharted territory. Hence the importance of finding synergy between a variety of types of expertise”, says Linden.
Hans Linden, Programme Manager Brightsite:
“This project is challenging; scaling plasma technology up to an industrial scale is pretty much uncharted territory.”
“We’re operating in a new field. The thinking style that predominates in traditional industrial processes doesn’t apply here. And so we need to adapt our way of thinking. We have plenty of knowledge of classical scaling up in traditional chemistry. But we don’t yet know much when it comes to how scale-ups work in the case of plasma and what kinds of problem or challenge we’ll run into. Plasma technology involves warming up the system in a different way, which requires a different way of working. Consequently, we as a team have to ask much broader questions. After all, we don’t yet have a precise picture of the frameworks within which we’ll need to think and work when it comes to process and project risk analysis. In process terms, you try to imagine what it will look like on a large scale and then reverse-engineer the envisaged solution. What helps in that regard is that our expertise enables us all to view the challenge from different angles and make a valuable contribution”, explains Hans Kroon, Sustainable Process Development Consultant at Brightsite.
Scale-up in the Brightsite plasma lab with a Plasma ARC setup with a maximum power of 20 kW.
Old process revamped
The basis for the plasma process (the Hüls process) was developed in Germany in the last century and entails methane being converted to hydrogen and acetylene. “This process is our reference process. It has never been revised and although universities and other parties have done a lot of research into it, imitating the process on a smaller scale continues to prove tricky. In view of the fact that the technology hasn’t been modernised, we expect to be able on the latest insights to make the process more efficient and more selective. This will make the development extremely interesting”, thinks Creyghton.
“We work with several pieces of equipment of different sizes in the plasma lab. We’re keen to understand how the process behaves at different scales and why. The better our understanding of this, the faster and better we’ll be able to scale things up accordingly. The time spent in the reactor is in the order of microseconds and at extremely high temperatures of up to 10,000 degrees Celsius. The trick is to freeze the reaction at exactly the right time, which is a challenge, particularly at these temperatures. What we’re doing is a combination of modelling and experimental research, which makes this programme fascinating”, states Kroon.
Hans Kroon, Sustainable Process Development Consultant:
The combination of modelling and experimental research makes this programme fascinating.”
Thomas Butterworth, assistant professor at UM (Faculty of Chemical Engineering): “It is important that we learn more about the plasma processes and chemical kinetics using more fundamental research.
For example, we want to understand exactly how the plasma heats the gas. With the use of simulations and our unique laser experiments we can gain fundamental mechanistic understanding of what happens at lab scale. We can then translate that to larger scales, where we hope to be able to extrapolate our knowledge to different operating conditions based on our fundamental knowledge. The NXTGEN project gives us the time and space to investigate and answer the important questions about scale-up. It is valuable to build knowledge together in this way – combining industry expertise with academic insight. We also notice that the scientific world is looking at us with curiosity – they want to see if we will make it a success. Not surprisingly, we are one of the first research groups looking to scale up plasma technology.”
Thomas Butterworth, assistent professor at UM:
“It is important that we learn more about the plasma processes and chemical kinetics using more fundamental research.”
Consortium for developing plasma equipment
Linden: “In addition to our core team, we’re involving other parties in this project through a consortium. A total of thirteen parties from the hightech and chemical industries are now involved, supported by UM, DIFFER and TNO. Most of the companies are Dutch, though we also have a Canadian and a German company in the mix.” Creyghton: “It’s important for us to turn the knowledge that we’re collectively gaining into something useful that we can present to the parties who will ultimately be the ones producing the equipment. They’ll only be able to produce what we need with clear information.”
What is plasma technology?
Plasma technology has the potential to electrify chemical processes with (green) energy and produce raw materials for the chemical industry without releasing CO2. Plasma is also referred to as the fourth state of matter, alongside solid, liquid and gas. When a gas is introduced into a sufficiently strong electric field, it enters a state in which gas particles ionise. This ionised gas comprises gas molecules and reactive particles such as ions, electrons and radicals. This combination of reactive particles makes (new) chemical reactions possible. The temperature is extremely high at the heart of this electric flame, the heart of the plasma cloud. Molecules are very quick to split and form in these conditions. And the fact that a plasma is generated using electrical energy means that the process is exceedingly sustainable when green electricity is used.
Brightsite Plasma Lab
Brightsite Plasma Lab opened in 2021. This unique lab is a place where Brightsite partners UM, TNO and Sitech Services work together with students and businesses from the chemical industry to optimise existing plasma technology and develop new plasma processes. By combining the possibilities presented by plasma technology in Brightsite Plasma Lab with innovative, state-of-the-art technologies and by also conducting fundamental research we expect to be able to make some significant breakthroughs in terms of sustainability. Setting up Brightsite Plasma Lab marks the first major step, taken efficiently and sustainably, towards new industrial applications for plasma technology in chemistry. As stated, high-quality conversion of methane is one of Brightsite’s pillars when it comes to plasma technology. The focus initially is on converting methane to acetylene and the next step could be the direct conversion of methane to ethylene. Other opportunities for the future are also being explored. “Plasma technology can be used not only for methane valorisation but also within the nitrogen chain for the production of fertiliser and plastics. As we see it, it’s the new chemical process technology based on green electricity”, Linden concludes.