How to improve the campaign Delta a 140 ton capacity furnace

In the second half of 2018, TECNOLITA was consulted by a customer who owns a 140 ton capacity three-phase electric arc furnace.

This furnace operates without opening the vault, as the preheated metal scrap is loaded through a metallic conveyor and the pig iron
is fed into the electric oven through a transfer chute. This customer’s complaint related to the low performance of the delta used.

We found that our client used a delta, which was installed inside a water-cooled metal ring.

The average delta campaign was in the order of 80 races, what caused to having to switch it every week.

The operational interruptions for welding the refrigerated ring tubes that punctured during operation and the successive changes of the
deltas provided high levels of power off and low productivity.

This information were sent to TECNOLITA’s Engineering Department, which started to develop a new project that contemplated the
following conditions:

1- Use of dry metal ring without water cooling;
2- Modification of the refractory profile in order to better adapt to the electric oven;
3- The adaptation of the refractory part to the existing operational model.

After 6 months of work, monitoring of tests, analyzes and modifications in the original project, we were able to produce, install and
operate a delta, which obtained a campaign of 655 runs, operating for more than 40 days without any interruption.

The final results of this development can be seen in the table below: