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How to optimize EAF process to achieve significant cost reductions and productivity improvements

by | Oct 29, 2020

Requirements of producing steel with lower CO2 emissions are increasing all the time. The Electric Arc Furnace (EAF) process is an effective way of making steel, but it is still a very energy-intensive process. The EAF process can be optimized to be more energy efficient, but how can this optimization be done?

The EAF process is usually controlled with statistic methods. These methods are not ideal as there is no exact information about the input material content and material differences between heats. In addition, traditionally there has not been measured information available about the melting progress due the extreme conditions inside of the furnace. In some cases, process control may be based only on operator’s knowledge and expertise. Extreme conditions make it difficult to control the process. What if we could see and measure what happens inside the EAF in real-time?

With real-time melting information optimization and dynamic control of different phases and optimizing the EAF process becomes possible. For example, a simple use could be optimal timing of additional scrap charges. The additional charge is loaded optimally when there is enough room in the furnace for the new charge. Another example is controlling the furnace power optimally based on the progress of scrap melting. Optimizing the EAF power based on the melting information will improve the energy efficiency and tap-to-tap times. Also, oxygen and carbon injection timing could benefit from melting information.

How to measure the EAF process in real-time?

The conventional ways to measure the EAFs and the phenomena inside of EAF, has had some limitations. For example, off-gas analysis and side panel cooling water analysis suffer from significant delays. It takes time for the gas to travel to the sensors or for the water to heat up in the side panels. Furthermore, it is very difficult to interpret why has the off-gas temperature or side panel temperature increased. These limitations have prevented reliable real-time control – until now.

Optical emission spectrometry (OES) is an analytical technique to break down and examine light emitted from different sources. This method is usually used in detecting different elements in a sample by analyzing the light that they emit when excited (with laser/spark). However, this can be applied into hot metallurgical processes too. For example, EAF emits excessive amount of light during the heat and the melting progress can be measured observing the changes in emitted light. This makes real-time measurements possible but gives also other information such as slag composition and temperature.

Luxmet’s optical technology monitors light from the EAF process. This makes it possible to gain real-time measurements from inside the EAF enabling dynamic and automated process control. Luxmet’s solution ArcSpec, system for measuring and controlling EAF’s, has been proven to significantly improve EAF energy and process efficiency. In addition, the environmental benefits are significant. With our technology is possible to make more steel with less emissions!

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