An evaluation of the applicable new low-carbon technologies in integrated iron and steel plants

Iron and steel production is an industrial sector that involves energy-intensive processes and has a high share of fossil fuel use. Therefore, it accounts for 7% of global greenhouse gas emissions. Existing emission reduction technologies are insufficient for reducing carbon emissions in this sector. This thesis analyzes low-carbon technologies for integrated production facilities (Kardemir, Erdemir, and İsdemir) in Türkiye. Data on emission reductions were collected from the monthly and annual activity reports published by the facilities in 2022 and 2023. The main processes that cause carbon emissions in the iron and steel production process are coke and sintering plants, blast furnaces, and basic oxygen furnaces. In addition, lime factories also cause carbon emissions to provide production that can enter blast furnaces. The emission reduction technologies obtained from the studies conducted for this sector are summarized under three (3) main headings; alternative raw material use, carbon-free reducers/fuel substitution, and carbon capture and storage. The applicability of the investigated technologies to integrated plants in Türkiye was evaluated using the DEMATEL technique in three (3) criteria branches (applicability, carbon reduction rate, and cost). As a result of the evaluation, it was determined that the fastest applicable, highest carbon reduction rate, and lowest cost technologies in Türkiye are alternative raw material use technologies. In the application area of alternative raw material use, it has been determined that the coal blending model technology provides a greenhouse gas emission reduction of up to 73.66% if applied in Türkiye'sTürkiye's integrated plants. It is also seen that the carbon reduction rate for this technology is in direct proportion to cost and applicability. It has been determined that the most important criterion for selecting non-fossil reductants/fuel substitution technologies is the carbon reduction rate. It has been determined that if the non-fossil reductant technology with the highest carbon reduction rate is applied in integrated facilities in Türkiye, a 75% greenhouse gas reduction can be achieved. If the use of blast furnaces is indispensable, it has been determined that hydrogen supplementation to the tuyeres of direct furnaces also reduces greenhouse gas emission rates by 21.4%. On the other hand, it has been observed that carbon capture and storage technologies are still almost non-existent in Türkiye and that an infrastructure has not yet been established, especially for studies in the storage area. The most important obstacle to implementing this technology has been revealed to be cost. If the necessary steps are taken, greenhouse gas emission reductions of up to 93.26% can be achieved if these technologies are implemented in integrated facilities in Türkiye.