A circular economy for carbon – the key to a sustainable chemical industry

Whether it is wind turbine materials, textiles, plastic coatings, or cars: almost everything is based on carbon. In the chemical industry, carbon has been a basic raw material since the very beginning. Most carbon sources currently in use have fossil origins, such as crude oil, natural gas, or coal, and are extracted from the ground. However, these resources are only available in limited quantities. They also release large amounts of CO₂ through combustion or decay, which accelerates climate change. One solution is to shift the industry toward renewable carbon. Adrian Brandt explains what renewable carbon is and how such a switch can succeed. As head of the Bio-Renewable Materials Research Platform for Adhesive Technologies at Henkel, he is addressing a key question: How can raw materials based on renewable carbon – and bio-based materials in particular – contribute to a more sustainable future for industry?

1. What is renewable carbon?

Adrian Brandt: Renewable carbon includes all carbon sources that avoid or replace the use of fossil carbon, for example natural gas, petroleum and coal. We consider three sources for renewable carbon: biomass, recycled plastics and materials, or CO₂ from air and exhaust gases.

2. How can materials based on renewable carbon be obtained?

Adrian Brandt: Raw materials and chemicals for adhesives or other applications can be obtained from biomass, for example. This is one possible source of materials based on renewable carbon. Simply put, biomass includes everything that grows and is green at some point, meaning all organic substances of plant origin. We can distinguish between three generations: First-generation biomass includes the fruit of the plant, for example starch plants such as corn or potatoes. The rest of the plant, the leaves, and stems, belong to the second-generation. Experts call this lignocellulose. Algae represent the third-generation biomass.
Then there is the possibility of obtaining renewable carbon through recycling. You essentially can recycle anything, from materials and waste based on renewable carbon (from biomass, recycling or CO₂ from air and exhaust gases) to fossil carbon. Chemical base materials can be extracted from waste like plastic packaging. With the help of new technologies, basic chemicals such as ethanol can also be obtained from the air or exhaust gases.

3. How does it work exactly? How can CO₂ be extracted from air and exhaust gases?

Adrian Brandt: CO₂ can be filtered out of the air. This method works wherever there is an overproduction of energy – for example in wind power or photovoltaic plants – or where waste is generated as heat. This excess energy can be used to filter CO₂ from the air and convert it, for example, into chemicals such as methanol, formic acid, methane or fuels. Fermentation plants are a concrete example of waste gas utilization. These are placed near steel or cement plants or other industrial facilities that produce a lot of waste gases. The fermentation plant sucks in the CO₂ from the exhaust gases and special bacteria convert it into chemicals or raw materials. This way a facility can produce about 40,000-50,000 tons of ethanol per year.

4. Which process is the most promising? And can a ‏(long-term) switch to renewable carbon in the chemical industry succeed?

Adrian Brandt: We need all three processes. It is certainly most important that we make progress in recycling waste, because that will represent the largest amount of renewable carbon in the future. However, that alone is not enough, because process energy and heat must also come from renewable energy sources. The shift from fossil-based to renewable energy in the energy sector is comparable to the shift from fossil carbon to renewable carbon as a feedstock in the chemical industry. Waste, biomass, and CO₂ must become the new raw materials for the chemical industry instead of natural gas and crude oil. We can only achieve this change by creating a cycle. We need to leave fossil carbon in the ground and instead work with carbon that circulates above the ground, for example in household waste. Or we can pull the CO₂ directly from the atmosphere. That's the vision: a circular economy for carbon.

5. You are the head of the "bio-renewables" research platform at Henkel. What's it all about?

Adrian Brandt: The platform was set up in 2015. In my team, we do not develop final products, but we focus on renewable carbon-based raw materials. Our goal is to bring more products to the market that are based on renewable carbon. To achieve this, we consult departments and colleagues internally and build a network with suppliers, start-ups, and scientific institutes externally. Together, we not only want to research the materials of the future in a timely manner, but also increasingly bring renewable raw materials into our products that are already available today. We demonstrate what is possible and test how new adhesive solutions can be implemented. We also have a laboratory where we produce raw materials ourselves – proactively but also on request. We develop new technologies that make our adhesives better and can also fully meet future customer requests. To do this, for example, we use unique structures from nature to gain property advantages such as very good adhesion, chemical resistance, or UV stability. So, in short, the aim is to meet all customer requirements in the future with products based on renewable carbon.

6. How do Henkel's adhesives technologies and solutions specifically contribute to a more sustainable future?

Adrian Brandt: We want to develop adhesives with the highest possible proportion of renewable carbon because raw materials account for the largest share of our overall CO₂ footprint. Our production itself accounts for only a small part. The CO₂ footprint of a product can theoretically be reduced to almost zero if renewable energy is used across all steps of the process. This is an impossible goal to achieve with fossil raw materials. To give an example: in the electronics sector, we want to produce every polyurethane adhesive with at least 50 percent renewable carbon by 2025. On top of raw materials, we also want to offer solutions that enable recycling. For smartphones, for example, we want to ensure that the adhesives will hold everything together well. At the same time, we want to make sure that the adhesive can be easily detached to facilitate the recycling process.