The thermal performance of water cooled panels in electric arc steelmaking furnaces.

The initial stage of the work was a study of an 80 tonne industrial furnace, taking observations, panel water temperature data and samples of slag layers from the sidewalls. This resulted in a simple model of layer formation which explained the observed structures, and also the effect of slag layer thickness on heat losses was examined.However, the complexity and variety of structures found were such that a full series of direct thermal conductivity measurements was deemed impractical, and so a theoretical model to calculate the thermal conductivity of complex structures from the thermal conductivities of it s components was developed. Other aspects of heat transfer both within the furnace and from the furnace interior to the water cooling were also explored.In order to obtain a reliable value of thermal conductivity for the slag component of layer structures, a technique was developed to measure the thermal conductivity of the slag. This consisted of firstly determining a viable route for the production of homogenous samples, followed by the design, construction and refinement of an experimental measuring rig. After a large number of preliminary measurements, a series of thermal conductivity values at temperatures between 300 and 800 C were measured using operating conditions calibrated against a heat storage brick sample of known thermal conductivity. These results were used to provide the data for the theoretical thermal conductivity model, which was then applied to real structures for which thermal data was available. Comparison of the results showed good correlation.Finally, in the appended case study, the heat loss calculation was applied for various furnace situations to identify the potential heat loss savings that could be achieved by controlling the slag layer thickness and structure, and the financial implications.