Research and cooperation are the keys
LANXESS has entered into a cooperation on circular economy with the Karlsruhe Institute of Technology (KIT) in the field of recycling. The pyrolysis procedure is a thermochemical recycling process that complements mechanical or physical and solvent-based methods. It opens up the possibility of generating valuable raw materials for the chemical industry from the waste flows.
In the interview, Razan Alsharqawi, PhD student at the KIT, Philipp Junge, Head of the New Mobility and Circular Economy group initiative at LANXESS, and Simon Höwedes from the Polymer Additives business unit talk about recycling flame retardants.
Mr. Junge, what exactly is the cooperation about?
For our polymers – that is, plastics – there are already good solutions for making them available again as raw material. This process is considerably more complex for our additives. Bromine-based or phosphorus-based flame retardants, for example, still present challenges when it comes to recycling. But because these base substances are valuable and our aim is, of course, to recycle all fossil base elements as far as possible in the interest of a circular economy, we are investing in research here. Our goal is to arrive at a recovery method with which we can recycle our additives almost completely on an industrial scale.
Ms. Alsharqawi, you are investigating the pyrolysis procedure for bromine-based flame retardants as part of your doctoral thesis. What are the problems to be addressed?
Razan Alsharqawi: As Mr. Junge already pointed out, pyrolysis is not a completely new procedure. If we take relatively pure polymers like the ones found in packaging material, the method is close to being perfected. At the end, we have what is known as a secondary raw material in the form of pyrolysis oil. It can be used in many different ways. It can either be added to light gasoline, or, after fractionation, it can be used as a raw material for plastics production. Many pure polymers consist mainly of carbon and hydrogen. The bromine in flame retardants adds a heteroatom that can be present as a liquid hydrocarbon compound. This, in turn, decreases the quality of the pyrolysis oil in the end. Complex procedures for separating the bromine already exist. I am now researching an optimized method for separating bromine during pyrolysis. Optimum temperature control is one of many questions that present themselves here. It is not easy to find the silver bullet that will also satisfy the industry.
"Our goal is to arrive at a recovery method with which we can recycle our additives almost completely on an industrial scale.”
Philipp Junge,
New Mobility and Circular Economy group initiative at LANXESS
Simon Höwedes: At PLA, we produce not only bromine-based, but also phosphorus-based flame retardants. Here, too, we want to examine how we can extract the purest possible secondary raw materials from plastics to which flame retardants containing phosphorus were added. In contrast to bromine, phosphorus remains in the pyrolysis coke as ash.
Razan Alsharqawi: That’s right. Depending on the feedstock and procedure, different quantities of pyrolysis gas, pyrolysis oil, and pyrolysis coke are created. Of course, we always want to obtain as much oil as possible. That is what I am trying to optimize with flame retardants containing phosphorus as well.
"It is not easy to find the silver bullet that will also satisfy the industry.”
Razan Alsharqawi,
Doktorantin at the KIT
(Karlsruher Institut für Technologie)
Will these procedures be cost-efficient in the foreseeable future?
Philipp Junge: That is the goal of our research. The fact is that the pyrolysis method offers the unbeatable advantage that separating chemically bound substances such as bromine and phosphorus requires a relatively small amount of energy. This shows once more that the industry must remain open to all recycling methods. In the end, a mixture of mechanical, physical, and chemical recycling will lead us to the best results. I am optimistic that the circular economy will prevail. There is a great demand for secondary raw materials even today. Customers pay higher prices for them, too. As the awareness for sustainable production increases, so does the pressure from the customers’ side to use sustainable, that is recycled, products.
"In contrast to bromine, phosphorus remains in the pyrolysis coke as ash.”
Simon Höwedes,
Polymer Additives Business Unit, LANXESS
Which prerequisites would still have to be met in order for the circular economy to gain momentum?
Philipp Junge: I think we’re generally quite far along in the chemical industry. Our plants are largely optimized, and we are not wasting energy and resources. Under the umbrella brands Tepex and Durethan, LANXESS is launching two new compounds that consist almost entirely of renewable resources. And this leads us to another key topic: In the long run, we must think about every product starting from the end. The key phrase here is “safe and sustainable by design.” What exactly is associated with this approach is currently being worked out in what is known as the Green Deal in the EU. Closed-loop material cycles constitute a central aspect here.
In a true circular economy, there shouldn’t be any landfills anymore. How can we achieve that?
Philipp Junge: I can only speak for our products here for the time being. We are dependent on external partners who collect the materials and put our products in their yards. After all, we are not a logistics company that can do this. And of course, there is currently still a lack of affordable green energy that we need for such an immense task, in addition to many other things. There is still a lot to do here, and in order for the circular economy to start running one day, we need to work together closely with partners beyond our industry to develop new approaches.
