Cleaner coke-making with non-recyclable waste plastics: A techno-economic assessment from a European perspective

Given the growing economic and environmental concerns about steelmaking processes, there are clear drivers to move towards a cleaner production. One step in this direction is to substitute part of the coking coal used in coke production with waste-derived materials that are typically landfilled or incinerated. In this paper, a techno-economic assessment from the point of view of a typical European coke-making plant was conducted. Two scenarios were evaluated: the Benchmark scenario (BS), involving coke production from fossil coal, and the AlterCoal scenario (AS), where 2 wt% of coal is replaced by AlterCoal® pellets made from non-recyclable waste plastics. Gross profit (GP) for 2019 and 2022 was the main indicator for comparing the economic performance of both scenarios. In both years, the AS had higher GP than the BS, mainly due to the reduced need of coal, and to the increased production of coke oven gas. An uncertainty analysis based on the Monte Carlo method showed that the economic volatility of the AS is lower than that of the BS, while a sensitivity analysis identified that coke, coking coal, electricity, and natural gas prices were the most influential variables on GP. Finally, direct CO₂ emissions were 11.2% lower in the AS compared to the BS, primarily due to biogenic carbon in AlterCoal® pellets leading to a more sustainable production process. This combination of unfavourable GP, high uncertainty, and high dependency on critical raw material prices in the BS elucidates the trend of various European steel plants reducing or suspending steel production.