Brightsite Plasmalab takes the next step with bench scale reactor


Plasma technology is considered to be a ‘game changer’ when it comes to electrification of processes in the chemical industry. However, scaling up plasma technology to industrial scale is still uncharted territory. The Brighsite Plasmalab is working hard at optimizing existing plasma technology and developing new plasma processes. The next important step in the scale-up process is the construction of a bench scale set-up for the conversion of methane to acetylene and hydrogen.

The chemical industry in the Netherlands must be climate-neutral by 2050. The use of green electricity plays a key role here. Amongst others, Brightsite focuses on plasma technology, an efficient electrical process for splitting and synthesizing molecules. With plasma technology, using electricity generated from sustainable energy sources, methane can be converted into hydrogen and high-quality hydrocarbons without releasing CO2 (see box ‘What is plasma technology?’). The process of methane atomization using plasma technology is an existing process, developed in Germany: the Hüls process. This process, in which methane is converted into hydrogen and acetylene, runs on a commercial scale (10MW per reactor, I a set of 4) in Germany. “We expect to be able to organize this process more efficiently with the latest insights, strive for better selectivity and see whether we can get by with less energy. We did have to start from ‘scratch”, says Dirk van den Bekerom, plasma technology expert at TNO, involved in the Brightsite Plasmalab. 

Crucial step toward application
“We are working on the industrial upscaling of plasma technology in the Brightsite Plasmalab through feasibility studies, process improvements and fundamental research. This starts with fundamental research on a small scale and at a low Technology Readiness Level (TRL). The next step is applied research on a bench scale and then working towards the realization of a pilot plant, possible another demo plant and ultimately making the step to a commercial plant (see Figure 1)”, says Wilbert Derks, active as project manager from Sitech at the Brightsite Plasmalab. “The research into the conversion of methane on a lab scale was successful and we are ready for the bench scale, the important second step. While in the lab setups (1-10kW), usually under vacuum, fundamental principles are explored and concepts that are essential for the fundamental understanding of the technology are proven, in this step we focus on validation and scalability. We are already trying to run the process the way it should eventually be run on a commercial scale. A first crucial step toward application”, Derks said.

Dirk van den Bekerom, plasma technology expert at TNO

“We focus on two technologies: arc technology and microwave plasma. Arc in particular has a bright future; it is a solid, robust technology that is easier to scale. And the basis of the bench scale reactor (50kW) that we are now building”.

(Figure 1)

Learning from bench scale
“As we move into pilot plant (TRL 6, 7), the stage is set to move out, out of the Brighsite Plasmalab. And then Brightsite spin-out Thoriant will continue to run the gauntlet”, Nicoleta Voicu, involved as plasma project manager from TNO, explains. “Thoriant will perform the formation of hydrogen and acetylene using arc technology on a scale of 500 kW. This requires a scale-up by a factor of 10 compared to the 50kW reactor we are currently making. In this next, advanced phase, the technology will be demonstrated in a relevant environment, closer to commercial application. The information we gain with our bench scale set-up is indispensable. We learn a lot in every step and that can then be taken to the next step”, Voicu emphasizes. 

Derks: “Our set-up is unique worldwide, a high power plasma arc for methane plasma pyrolysis. In addition to the tests we carry out with the arc reactor, we are building a calculation model in parallel, with which we try to predict and explain what comes out of the reactor. We will test and examine different configurations and compare them with the model. By combining the two, we can connect theory (model) and practice.” 

Getting all parties on the same page
“The biggest challenge in this phase was in the design of the arc reactor. After two years, we are now almost finished with its construction. We expect to have the reactor operational soon. Because it is a very complex process, involving several parties with specific expertise, it was important to get and keep all participants on the same page. This new set-up includes plasma technicians, engineers, manufacturers and safety specialists. In addition to Brightsite partners Sitech, TNO, Maastricht University (UM) and Brightlands Chemelot Campus, several other parties play a crucial role, including Elektravon, BAM, Kuijpers, RVO, Ebert HERA, Array, PyroGenesis Canada and OCI. Due to the different cultures, it is quite difficult to ensure that everyone speaks the same language. But now we understand each other and it is clear to everyone who plays what role. It is an exciting project, but very valuable for all partners,” says Voicu.  

Sitech particularly contributes knowledge about scaling up and engineering. TNO will be responsible for the daily use of the arc reactor and will interpret the results with a team of researchers. And OCI has invested because they see this process as one of the options for future hydrogen sources for their plants. 

The core team at the 50 kW bench scale reactor in the Brightsite Plasma Lab: from left to right Nicoleta Voicu (plasma project manager at TNO), Dirk van den Bekerom (plasma technology expert at TNO) and Wilbert Derks (project manager Brightsite Plasma Lab at Sitech)

Using methane in a high-quality manner
Why convert methane using plasma technology? “In the future, factories such as naphtha cracking plants will remain, but CO2 emissions will have to be reduced. Whereas methane – released as a byproduct (10%) in the cracking process – is now used to heat the cracking process, in the future, electricity will be used as the energy source. When crackers are heated electrically, the methane produced is available for other, valuable uses. With the help of plasma technology we can make optimal use of methane,” Voicu explains. The focus now is on the formation of acetylene, and a next step could be the direct conversion of methane to ethylene, but there are several possibilities with plasma technology. It can be applied not only to hydrocarbons, but also within the nitrogen chain. For example, thanks to an awarded MOOI (in Dutch Mission-Driven Research, Development and Innovation) grant, the Brightsite Plasmalab is also working on so-called nitrogen fixation. This research arm, just like methane, is being developed simultaneously on several scales. 

What is plasma technology?
Plasma technology has the potential to electrify chemical processes with (green) electricity and produce hydrogen and raw materials for the chemical industry without releasing CO2. Plasma is also called the fourth aggregate state, in addition to solid, liquid and gas. When a gas is introduced into a sufficiently strong electric field, a condition is created in which gas molecules ionize. This ionized gas consists of gas molecules and reactive particles such as ions, electrons and radicals. This combination of reactive particles enables (new) chemical reactions. In the center of this electric flame, the center of the plasma cloud, the temperature is very high. Under these conditions, molecules can be split and formed very quickly. And because a plasma is formed with electrical energy, the process is very sustainable when green electricity is used.

About the Brightsite Plasmalab
The Brightsite Plasmalab is a unique lab where Brightsite partners UM, TNO and Sitech, together with students and companies, optimize existing plasma technology and develop new plasma processes. By combining the capabilities of plasma technology with innovative state-of-the-art technologies in addition to conducting fundamental research, we expect to make significant breakthroughs in sustainability. High-quality conversion of methane is one of Brightsite’s pillars in the field of plasma technology. The focus is first on conversion to acetylene and the next step could be directly converting methane to ethylene. Other possibilities for the future are also being considered.