Developments Toward an Intelligent Electric Arc Furnace at - Tenova

Figure 4: Water Leak Detection Interface
The operator can set three kWh benchmarks allowing the division of a charge into four intervals (early melting, melting, early refining
and refining). For each of these intervals two thresholds are set, one for absolute hydrogen concentration in the furnace and the second
is for the relative concentration of hydrogen with respect to carbon monoxide. Functionally, this system provides the flexibility to
assign different thresholds for alarming depending on the various stages of the process. For example, during refining hydrogen levels
and the ratio of hydrogen to carbon monoxide are typically lower than during the initial stages of melting. This is due to the higher
rate of methane usage during melting and also due to the flashing of oils from the scrap or the presence of water in the charge that is
not present during refining.
EFSOP ® RESULTS
Typically, the benefits due to EFSOP ® optimization are determined by comparison to a representative historical baseline. Ideally, a
long term baseline is used to account for seasonal affects. At CMC Texas, the injectors were changed at the end of 2005. Some
performance benefits were noted during this period that was not attributable to EFSOP ® . Therefore the baseline period was based
only on the operation during the whole of January 2006. Figures 5, 6, 7 and 8 are, respectively, the average monthly specific
consumptions of electrical energy, natural gas, oxygen, and carbon per inventory cast ton. The plots contain the averages for Oct-05,
Nov-05, Dec-05, the baseline month (Jan-06) and the EFSOP ® evaluation period (February 20 th to march 19 th , 2006).