Heat integration and operational optimization of an austenitization furnace using concentric‐tube radiant recuperators. Issue 7 (26th October 2018) - Ganesh, Hari S.
Abstract : This paper presents a model‐based study of the impact of implementing radiant (radiation‐dominated) concentric‐tube recuperators on fuel use in an indirectly‐fired industrial heat treating (austenitization/quench hardening) furnace. The recuperators recover some of the waste heat from the burner exhaust to preheat the inlet air to the burners, thus reducing the amount of fuel required for combustion. The novelty of this work consists of developing a physics‐based model of a recuperator, which captures local gas‐to‐surface convective heat transfer and long‐range surface‐to‐surface radiation interactions, and using the model to analyze and optimize the energy use of the furnace. An iterative algorithm is proposed to solve the poorly‐conditioned energy balance equations. The steady‐state system operation is optimized using surrogate models. Extensive simulation studies demonstrate that heat integration reduces fuel consumption significantly without affecting product quality. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16414 2019