CO2 to Monomers

Chemical recycling of plastics through direct synthesis of monomers from CO2

Objective

In order to close the plastic recycle loop, CO2 from plastic incineration should be converted back to new plastic.

Background

The unsaturated hydrocarbons ethene, propene, and butenes, collectively called light olefins, and the aromatic molecules benzene, toluene and xylene are the main monomers (or monomer precursors) in the manufacture of plastics. Since light olefins and aromatics are mainly produced from crude oil there is an increasing demand for recycling to make the consumption more sustainable. The best way is direct recycling by melting into new products. However, it has recently become clear that only a fraction of the consumer sorted plastic is possible to recycle directly. Some of the remaining plastic could be chemically recycled (e.g. depolymerization or pyrolysis to a liquid resembling crude oil, see project Bi-cycle), but some plastic will inevitably be incinerated, to avoid it ending up on landfills, which is worst way of handling waste.

The project

This project develops a process for direct conversion of CO2, which could be captured from waste incineration, and H2, which could be obtained from water electrolysis, into light olefins and/or aromatics as plastic monomers or monomer precursors. Combining commercial high or ultra-high temperature water gas shift catalysts with systematically varied, zeolite based methanol to olefins/aromatics catalysts, dual catalyst systems for direct conversion of CO2 to olefins/aromatics will be prepared. These catalyst systems will be evaluated in terms of their structure-activity-selectivity relationship using a flow reactor setup, advanced spectroscopy and electron microscopy. This will enable evaluation of the potential for a process converting CO2 to plastic monomers and lay the foundation for future rational improvements of the catalysts and process conditions. 

Independent Research Fund Denmark, Technology and Production Sciences.

For more information, contact:
Martin Høj (Project manager)
Jakob Munkholt Christensen
Michael Thorstein Nikolajsen (PhD student)

 

Plastic recycling figure

Contact

Martin Høj
Associate Professor
DTU Chemical Engineering
+45 45 25 28 42

Contact

Jakob Munkholt Christensen
Associate Professor
DTU Chemical Engineering
+45 45 25 28 10

Contact

Michael Thorstein Nikolajsen
PhD student
DTU Chemical Engineering
+45 27 59 38 67