(414b) Towards a Circular Chemical Industry: Mapping the Flow of Fossil Carbon through Chemical Manufacturing Processes

The rising levels of carbon dioxide in the atmosphere threaten humanity with erratic changes in global weather, better known as global climate change. Researchers have drawn many parallels between the ongoing Covid 19 crisis and the incumbent consequences of climate change.^{1, 2} This naturally necessitates the need for urgent and sustainable action to reduce greenhouse gas emissions. The global chemicals industry has shown considerable decarbonization potential, accounting for 7% of the world’s emissions.³ This fraction greatly increases when the cement or iron and steel industries are lumped in with chemicals manufacturing.
Various sources of literature identify hotspots of greenhouse gas emission in the path to deep decarbonization. In this pursuit, modelling of carbon flow is an important step to pinpoint the sectors and processes with the greatest carbon footprint. Existing diagrams, such as the ones built by the Lawrence Livermore National Lab or the Stanford Global Climate and Energy Project (GCEP) suffer from aggregation of sectors and processes and thus do not offer complete insight into the problem.
In this work, we develop a steady-state material flow model of the chemical industry. This model will trace the flow of carbon from fossil, biomass, and other feedstocks and fuel sources, to intermediates, and finally valuable products, byproducts and emissions. To develop this model, we rely on process data and models of the chemical and petrochemical industries obtained from existing studies about the chemical industry,^{4, 5} the economy,^{6, 7} government databases,⁸ life cycle inventory databases,^{9, 10} and greenhouse gas emissions inventories.^{11, 12} We use fundamental material and energy balance models with stoichiometric information to estimate missing data and reconcile available data. Results are represented in the form of a Sankey diagram to facilitate a graphical view of the flows and opportunities for improvement.
We demonstrate how this study aids the identification of specific processes for adoption of alternatives such as electrification, hydrogen based manufacturing and carbon capture, utilization, and storage. This model lays the foundation for further work towards the vision of a carbon neutral and circular chemical industry that is also economically, ecologically, and socially sustainable.

References

¹ Rubén D. Manzanedo and Peter Manning. COVID-19: Lessons for the climate change emergency. Science of the Total Environment, 742:140563, nov 2020.
² David Klenert, Franziska Funke, Linus Mattauch, and Brian O’Callaghan. Five Lessons from COVID-19 for Advancing Climate Change Mitigation. Environmental and Resource Economics, 76(4):751–778, aug 2020.
³ Maria van der Van, Yoshimitsu Kobayashi, and Rainer Diercks. Technology Roadmap: Energy and GHG Reductions in the Chemical Industry via Catalytic Processes. Energy Technology Perspective, pages 1–60, 2013.

⁴ Peter G. Levi and Jonathan M. Cullen. Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. Environmental Science and Technology, 52(4):1725–1734, feb 2018.
⁵ Sean E. Derosa and David T. Allen. Impact of natural gas and natural gas liquids supplies on the united states chemical manufacturing industry: Production cost effects and identification of bottleneck intermediates. ACS Sustainable Chemistry and Engineering, 3(3):451–459, mar 2015.
⁶ Stanford University - The Global Climate and Energy Project). https://gcep.stanford.edu/.
⁷ Shweta Singh and Bhavik R. Bakshi. Accounting for emissions and sinks from the biogeochemical cycle of carbon in the U.S. economic input-output model. Journal of Industrial Ecology, 18(6):818–828, dec 2014.
⁸ Lawrence Livermore National Laboratory. https://www.llnl.gov/.
⁹ Ecoinvent version 2.2. https://www.ecoinvent.ch.
¹⁰ United States Life Cycle Inventory (USLCI). https://www.nrel.gov/lci/.
¹¹ United States Environmental Protection Agency. https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a....
¹² IPCC - The Intergovernmental Panel on Climate Change. https://www.ipcc.ch/.