EAF Heat Recovery from Incident Radiation on Water‐Cooled Panels Using a Thermophotovoltaic System: A Conceptual Study

Abstract

In this paper, a conceptual study and quantification of using a thermophotovoltaic system (TPV) to convert incident radiation on furnace panels to electrical energy is presented. In typical electric arc furnaces (EAF), a considerable amount of energy is wasted during the melting process, that is, steel enthalpy, off-gas extraction, vessel cooling, slag enthalpy, and others. Although a remarkable share of the energy is wasted in circulating water, the contained exergy is simply too low to be considered for heat recovery (under 0.5% of input exergy) in comparison to energy content of the extracted gasses and slag. In the performed study, a TPV power output is calculated as a function of arc length, slag and bath height, zone temperatures, and emissivities. Two major changes to the existent EAF model were performed in order to estimate the TPV efficiency, that is, 1) the radiative heat transfer module has been re-developed to allow calculation of the incident radiation on the TPV, 2) the model has been extended with a TPV module, which is used to estimate the electricity produced by the TPV. The effects of TPV capacity, its distance from the slag layer and input regime on generated electrical energy are studied. The results have shown that a typical EAF, equipped with TPV system, can reduce average energy consumption by 4.8 kWh ton À1 , which corresponds to approximately 0.8% overall efficiency improvement. Moreover, the capacity factor of the installed TPV is predicted at 54% over a period of one year.

Calculation of View Factors in Electric Arc Furnace Process Modeling

“…Such process models that include a detailed treatment of the radiative heat exchange have been published by MacRosty et al, [ 4 ] Logar et al, [ 5 ] and, based on that, Meier et al, [ 6 ] Saboohi et al, [ 7 ] Fathi et al, [ 8 ] and Opitz et al [ 9 ] All of these models are based on similar assumptions regarding the geometrical conditions during meltdown, using a cone‐frustum‐shaped void in the scrap moving down and expanding outward as the electrode bores down toward the melt and the charge melts. Three phase furnaces are approximated with a single central electrode and electric arc.…”

Methods to optimize energy consumption in Conarc furnaces

“…The thermophotovoltaic system (TPV) [17,24] is a highpower density conversion technology, which generates electrical energy from the radiations emitted by a heated https://doi.org/10.1007/s42452-021-04852-6 Review Paper body. This system is promising as it promotes the utilization of a significant amount of the lost energy.…”

A Review of Mathematical Process Models for the Electric Arc Furnace Process

“…[ 34 ] Logar et al [ 35 ] based their work on a similar geometry and adjusted the calculation of view factors to reduce the number of empirical estimations used. In later works, Fathi et al [ 39,42 ] and Saboohi et al [ 43 ] included additional surfaces and a dynamic share of radiation of the energy emitted by the arc for more detailed studies of the radiative heat transfer. Meier et al [ 13,36 ] also based their work on Logar's model, adding the electrode and the gas phase including dust to the radiative heat transfer calculations.…”

“…The most basic type of a validation is to conduct a case study, in which a heuristic comparison between simulated heats and selected heats from an industrial EAF is conducted. [ 32,34,53,64,91–94,123,124 ] A common validation approach utilized in the majority of the presented noncommercial models [ 27,35,38,42,43,48,54,62,65,103,104,125–133 ] is to formulate a physical model with the literature data and validate it using point data from the refining period or tapping of industrial EAF. While steel and slag temperature and composition have high relevance to EAF operations, the lack of continuous variables in model training and validation makes it harder to analyze the sources of errors and makes it very challenging to validate the results during the heat.…”