Transient heat transfer computational model for the stopped aluminium reduction pot – Cooling techniques evaluation

Abstract

In aluminium smelters, cooling of a stopped reduction pot takes about seven days in a free convection environment before the relining process can commence. As the pot's steel component (potshell) is saved for the subsequent generation of pots, reducing the cooling time is desirable to ensure consistent smelter production. In this work, a 3-D Finite Element Heat Transfer (FEHT) model is developed, validated with experimental data and used to evaluate the effectiveness of forced convection cooling techniques for the pot. Two separate forced cooling techniques; parallel forced air flow and impinging jet air cooling are applied on the potshell and metal pad surfaces respectively. Air velocities ranging from 5 to 20 m/s are considered for both setups. Results showed that the metal pad forced cooling technique reduces the pot's cooling time significantly. The potshell cooling technique is limited by the high heat capacity of the back insulation layer and the thermal back diffusion from the pot's high temperature contents. The knowledge developed in this article is useful in designing and analysing suitable heat transfer tools for the stopped aluminium reduction pot.