Use of carbon dioxide as raw material to close the carbon cycle for the German chemical and polymer industries

Abstract

This article explores how far the use of CO₂ as raw material could enable the German chemical and polymer industries to contribute to a circular economy. Material Flow Analysis was conducted for all carbon flows for material use in Germany, comprising chemical production, polymer production, domestic use and waste management. For scenario modelling, Carbon Capture and Utilization technologies were included, and key parameters determining carbon flows were altered to show potential corridors for the future development. The results show that current carbon flows are dominated by fossil sources and are highly linear, with a secondary input rate of only 6%. Additionally, 12% (2 Mt/a) of the primary carbon input is lost due to dissipation. Currently available Carbon Capture and Utilization technologies would allow reaching a secondary input rate of 65% for the chemical industry. However, to achieve this rate between 80% (processes of direct synthesis) and 103% (methanol-based processes) of the total net supply for renewable electricity in Germany would be required in 2030 and between 41% and 50% in 2050. In contrast, the unavoidable substance related CO₂-point sources in Germany could probably fulfill the carbon requirement for material use of the chemical industry in 2050. The authors conclude that the utilization of CO₂ as a carbon source is necessary to close the carbon cycle where material or chemical recycling is technically not feasible or reasonable. The very high demand for renewable electricity indicates that the required production facilities for CO₂-based chemicals will probably not be completely based in Germany.

Keywords: Carbon dioxide utilization; Carbon recycling; Chemical industry; Circular economy; Resource availability.