No abstract

Waste heat recovery has a high potential for increasing the efficiency and sustainability of electric arc furnaces. In the present work, a dynamic model of a water cooled hot gas line is presented and validated with measurements of a newly installed electric arc furnace (EAF) with a waste heat recovery system. Due to necessary reconstruction work of the EAF, the cooling pass is upgraded to a heat recovery hot gas line. With hot water from the hot gas line saturated steam can be produced and fed into the existing steam net. The heart of the system is the water cooled hot gas line which is responsible for sufficient hot gas cooling on the one hand and adequate hot water generation for the steam generators on the other hand. The water cooled hot gas line is modeled in the commercial simulation software APROS and validated with measurements of the performance test during commissioning of the heat recovery plant. The simulation results are showing an excellent agreement to the measurements. The results embody that the model is both very reliable to estimate the transient behavior of the hot gas line and able to predict the operational process conditions.

Over the last years, waste heat recovery in steel industry attracted more and more attention. Environmental regulations, public funding as well as required revamps of old dedusting systems lead steel plant operators to discuss and to evaluate possibilities of recovering waste heat. The development of a waste heat recovery plant requires extensive knowledge as well as long experience of the entire plant, including water-steam cycle as well as EAF process, dedusting system and downstream waste heat consumers. Primetals provides innovative and reliable waste heat recovery solutions for EAF which are presented in this paper. An innovative waste heat recovery plant is introduced which was installed at Arvedi / Italy. Waste heat is used to produce steam for two pickling lines, which are in a large distance to the EAF. The substitution of the existing gas fired boilers lead to a decisive reduction of operating costs of the steel plant. A heat recovery plant was installed at steel plant Höganäs / Sweden, whereas hot water at high pressure is produced and utilized for the local district heating system. The paper demonstrates economic opportunities for efficient waste heat recovery in EAF based steel plants and reasonable integration of the waste heat recovery system into the dedusting line.