Off‐Gas Waste Heat Recovery for Electric Arc Furnace Steelmaking Using Calcium Hydroxide (Ca(OH)₂) Dehydration

Abstract

Off-gas waste heat recovery for electric arc furnace (EAF) steelmaking is challenging because high off-gas velocity, fluctuating temperature, and high dust contents must be considered. In addition to the harsh off-gas conditions, a heat storage system must be included to balance power-off times of the EAF during taping or charging. However, waste heat recovery offers a significant potential for further efficiency improvements in EAF steelmaking. Herein, a novel process concept for extraction, storage, and utilization of off-gas waste heat via entrained flow dehydration of calcium hydroxide (Ca(OH) 2) for efficient power generation is described. The use of waste heat exchangers is avoided, and small heat storage units are achieved. The process concept, Ca(OH) 2 dehydration and heat storage mechanism as well as important process parameters are discussed. Finally, the energy balance of the waste heat recovery process and further process improvements are presented.

Parametric Energy Efficiency Impact Analysis for Industrial Process Heating Furnaces Using the Manufacturing Energy Assessment Software for Utility Reduction

“…A study has found that furnaces consume about 30% of the fuels utilized in the industrial sector and 10% of the industrial electricity demand [12]. But the gases leaving the furnace contain a considerable amount of heat energy, resulting in the decreased thermal efficiency of furnaces, which could be improved by recovering the thermal energy that is present in off-gas [13].…”