The energy of exergy – analysis of different olefin production routes

Panel: 2. Sustainable production towards a circular economy

This is a peer-reviewed paper.

Authors:
Markus Fritz, Fraunhofer Institute for Systems and Innovation Research, Germany
Ali Aydemir, Fraunhofer ISI, Germany

Abstract

In order to achieve the greenhouse gas emissions reduction targets, there must be a significant reduction in all sectors. The chemical and petrochemical sector was responsible for 7 % of worldwide CO2 emissions and 10 % of worldwide industrial final energy demand in 2010. For this reason, efficiency potentials must be used or new production processes introduced.

In the context of decarbonisation, the focus is often exclusively on the energy perspective, since this provides the relevant information for investment decisions in the field of energy or greenhouse gas efficiency. However, for industries in which energy carriers are used both energetically and materially, a purely energetic analysis can only have limited informative value with regard to the efficiency of the entire production process.

An alternative to purely energetic analysis is exergy analysis, in which all relevant material flows for an analyzed process are included. In this context, an indicator for the efficiency of the overall process can be defined that combines energy and material flows. We therefore conduct such an analysis for the production of olefins by the steam cracking process. The required data is based on a virtual production plant according to the Best Available Techniques (BAT) document of the JRC. In addition, we analyze two possible future production processes and compare them with the current production process.

The future production processes consider the production of Olefins either from waste or from hydrogen and CO2. The exergy efficiency of the steam cracking process is around 56 %. The results show that the exergy efficiency cannot be increased with any of the possible future production processes we have investigated.

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