Germany's Evonik advances pyrolysis oil purification solutions

In the pyrolysis process, plastic waste is broken down into its chemical building blocks at high temperatures and in the absence of oxygen. The primary product of this process, pyrolysis oil, can supplement fossil feedstocks like naphtha derived from crude oil. Pyrolysis oil is further processed in steam crackers, which produce the essential building blocks for new plastics, such as ethylene and propylene. 

However, pyrolysis oil often contains impurities such as chlorine, nitrogen, or silicon, which can compromise the efficiency and operational safety of steam crackers. “Cracker operators apply strict quality standards to the feedstocks they use,” says Hendrik Rasch, who is responsible for Circular Packaging and Plastics Recycling in Evonik’s Next Markets Program. “This is precisely where our products come in. They help to significantly improve the quality of pyrolysis oil.” 

Evonik began developing technologies for pyrolysis oil purification several years ago, leveraging its extensive expertise in petrochemicals and feedstock processing. 

With its Purocel product line, Evonik now offers adsorbents specifically designed to remove impurities from pyrolysis oil. A standout product is Purocel 505, which combines two processes. First, chlorine atoms are separated from larger molecules in a catalytic reaction, and then the resulting hydrogen chloride is bound. This technology removes up to three times more chlorides from pyrolysis oil compared to conventional solutions. 

For applications with higher requirements, Evonik enhances adsorption with hydrotreating. In this process, hydrogen reacts with remaining impurities, converting them into volatile compounds. To further conserve resources, Evonik uses its recycled Purocel H catalysts in this process. 

In addition to chemical solutions, Evonik offers modular systems for seamless integration into existing facilities. With its Rocket Technology, Evonik provides pre-configured column modules containing adsorbents like Purocel 510. These units can be flexibly connected to both pyrolysis plants and steam crackers, enabling efficient purification without significant investments or prolonged downtimes. 

“Our solutions demonstrate how technological innovation can advance the circular economy,” says Rasch. “We are convinced that chemical recycling is a key pillar of a sustainable plastics economy.” 

Recycling contaminated and unsorted plastics remains a challenge. While mechanical recycling is an established method for pure plastic waste streams, such as PET bottles, a significant share of plastic waste consists of mixed and contaminated materials that are difficult to recycle mechanically. This is where chemical recycling comes into play. 

The global demand for chemical recycling is increasing, driven by regulatory frameworks. Evonik positions itself as a system partner for the industry, offering solutions tailored to diverse requirements – ranging from small-scale pyrolysis plants to large petrochemical complexes. 

Evonik’s technologies not only contribute to the circular economy but also strengthen the resilience of the industry. By utilizing pyrolysis oil, reliance on fossil resources is reduced, environmental impact is minimized, and supply security is enhanced.

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ALCHEMPro News Desk (JP)