| 1. |
- Biermann, Max, 1989, et al.
(författare)
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Evaluation of Steel Mills as Carbon Sinks
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The iron and steel industry is one of the industries with the largest global contribution to CO2 emissions. Possible mitigation options include use of biomass and carbon capture and storage. Combining these two mitigation options, this study evaluates the potential for BECCS at an integrated steel mill in Sweden. The injection of pulverized biocoal from torrefaction or pyrolysis into a blast furnace and CO2 capture by amine absorption of the blast furnace gas leaving at the top of the furnace can reduce CO2 site emissions by up to 61 %, when accounting for negative emissions (biogenic CO2 being captured). The mitigation cost are estimated to 43 – 100 € per tonne CO2 avoided, depending primarily on biomass prices and the share of biomass used in the process (the study assumes a cost effective capture rate of 84%). Besides a reduction in CO2 emissions, the study highlights the potential for green by-products from injecting biogenic carbon into the blast furnace in the form of renewable electricity and CO2 neutral steel. The study concludes that it is theoretically possible to reach carbon neutrality or even net-negative emissions in an integrated steel mill, but this would require considerable process changes and high demand of biomass. Nonetheless, the implementation of BECCS based on feasible biomass injection volumes in integrated steel mills is interesting as a near-term and possibly cost-effective option for CO2 mitigation.
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| 2. |
- Mocholí Montañés, Rubén, 1990, et al.
(författare)
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Large-scale Torrefaction of waste wood for pulverized-coal substitution in blast furnaces: Torero project
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of the Torero project is to be the world-first large scale implementation of the waste wood torrefaction for substitution of pulverized coal in blast furnaces. Steel making is highly dependent on coal for reduction of the iron ore in the blast furnace and for energy supply. Substitution of coal with biomass could effectively reduce CO2 emission in steelmaking. However, the steel making process has strict constrains on the properties of the fuel, making it difficult to use a heterogeneous fuel like biomass. In addition, the price of biomass, especially in a carbon constrained energy system, is higher than for coal. The Torero-project considers substitution of the pulverized coal used in the blast furnace with torrefied waste wood. The torrefaction process produces a bio-coal that is possible to mill and use in the present blast burners. Although waste wood is considered as a difficult, due to the high content of contaminants, which limits the alternative uses and, thus, makes it cost-effective in processes where it can be used. The process will be implemented at the ArcelorMittal site in Gent (Belgium), together with the sister project Steelanol, for microbiological fermentation of the carbon monoxide in blast furnace exhaust fumes to bioethanol. The combination of the two projects aims to convert waste wood to produce 80 million litres per year of bioethanol. This work is a first assessment of the Torero project concept. Process simulations are performed in Aspen Plus to evaluate the heat and mass balances of the integrated torrefaction process. The reaction mechanism of the torrefication process of the waste wood are based on small scale experiments and implemented into the reactor model. The ArcelorMittal plant in Ghent is used as a reference in the evaluation. The results of this investigation highlight performance, emissions and technical barriers including the effects of fuel properties and presence of trace species in the fuel.
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