Insights into the thermal and electric field distribution and the structural optimization in the graphitization furnace

The Acheson graphitization furnace (AGF), as a most energy-consuming equipment for graphite production, results in substantial thermoelectric losses during heating process. To improve the thermal efficiency, a method is proposed to optimize the structure of furnace core based on the thermoelectric field distribution. In this study, a numerical simulation using FLUENT software was adopted to explore the characteristics and coupling rules in relation to thermoelectric field distribution. Further optimize furnace core structure to achieve more suitable performance indicators, which include electrical heating efficiency and thermal efficiency. The results suggested that the changes of electric (power density) and thermal (temperature) fields with the layout of coke materials exhibited a consistence: the lower power density and temperature were observed at the position of graphitized coke, while the higher values were for calcined coke. The heat producer during the graphitization process was twofold: the electric heat and the transferred heat, and their proportion was confirmed as a range of 7:3–9:1. Under a fixed square side section, which is an optimal scenario, both thermal efficiency and electric heating efficiency with the furnace core length presented a parabolic variation. These findings may provide some guidelines and insights for a better design and operation of AGFs.