Carbon2Chem® as a step toward circular economy
Carbon dioxide is not only a chemical compound that damages the climate, due to its greenhouse effect, the gas can also serve as a raw material in different chemical transformation processes. In Germany alone, industrial chimneys, cars and homes emit about 900 million tons of CO2 each year. The major steel, chemical and energy industries should link up their value chains in the future, jointly saving valuable raw materials and reducing CO2 emissions (Wich et al., 2020).
In Europe a lot of funding is starting to be given to projects that help mitigate climate change, one of these is Carbon2Chem® which is an example of carbon capture and utilization (CCU) to take advantage of CO2 emissions from steel and chemical production, 50% of carbon dioxide emissions would be reduced. This innovative project shows a consistent level of energy demand in CCU compared to conventional steel and chemical production processes. The idea of this project is to connect the steel and chemical industry with the use of exhaust gases as a link (Abanades et al., 2015).
Figure 1. Block flow chart fot the conventional procoesses of steel production (TOP) and chemical synthesis (Botton) derived from dechema (Wich et al., 2020).
Figure 2. Block flow chart for a CCU process.
The efficient use of the process and the raw material in the industry, in this case CO2, means that no resources are wasted in a chemical process. Figure 1 shows how it is a typical process of the steel industry and the chemical industry separately, unlike Figure 2 which is generally a CCU integration of both industrial plants. Figure 3 shows how the carbon emissions to the atmosphere from the combined plant decrease significantly. The strong impact that the application of this type of system would have on the steel industry has been demonstrated by observing the potential for CO2 reduction of around 50%. If natural gas is replaced as a raw material as chemical energy by combustion, in addition to the substitution of electricity by renewable energy sources; emissions and energy consumption would fall significantly. The technologies currently being studied to lower the carbon footprint in the atmosphere are the use and viability of renewable energies.
Figure 3. Impact of the system expansion approach considering total CO2 emissions in ton of CO2 emissions in ton of CO2 per ton of crude steel: (A) CO2 emissions of the conventional blast furnace route (gray). (B) CO2 emissions of the conventional steel (gray) and conventional chemical production (dark blue). (C) CO2 emissions of the CCU process including the blast furnace route (left gray bars) and the chemical production via utilization of top gases (dark blue bars). Wind power as electricity source is assumed.
For a holistic comparison of the different CO2 reduction strategies-CDA, CCS and CCU-a general methodology beyond CO2 reduction and energy demand is mandatory. Recent literature reveals gaps in the strict methodology and the treatment of technological, economic, environmental and social aspects. The impact of a CO2 reduction strategy is determined by ecological, economic, technological and social criteria, which cannot be considered separately. Especially in the case of the circular economy, the assessment has to consider the whole system rather than individual value chains. Mandatory criteria for the representation of a circular economy such as the potential for reuse and substitution of fossil fuels are introduced and additional criteria are being discussed.
For a better understanding of the Carbon2Chem project as well as all its detailed information, please review the article cited.
Abanades, J. C., Arias, B., Lyngfelt, A., Mattisson, T., Wiley, D. E., Li, H., Ho, M. T., Mangano, E., & Brandani, S. (2015). Emerging CO2 capture systems. International Journal of Greenhouse Gas Control, 40, 126–166. https://doi.org/10.1016/j.ijggc.2015.04.018
Wich, T., Lueke, W., Deerberg, G., & Oles, M. (2020). Carbon2Chem ® -CCU as a Step Toward a Circular Economy. 7(January), 1–14. https://doi.org/10.3389/fenrg.2019.00162