EAF De-dusting System

1、EAF dust collecting

The dust collecting rate is the main factor to evaluate EAF de-dusting system. The dust collecting modes can be simply divided into: internal exhaust and external exhaust. The internal exhaust mode is mainly used for the smelting period with the feature of small capacity and good effect, which has been used widely for the dust removal systems of large and medium-sized electric arc furnace. The external exhaust mode is mainly used for collecting the out leak smoke during adding material, tapping and smelting period. When adding material and tapping, the EAF can not achieve the internal exhaust, so the external exhaust has to be applied.

Generally, the small and medium-sized electric furnaces will adopt external exhaust and medium and large size EAF will adopt combined mode of external and internal exhaust to more effective control and remove the dust in the whole smelting process of EAF.

Internal exhaust can be divided into two types: heat recovery and direct cooling of flue gas. The heat recovery takes use of the steam generated by waste heat boiler. Flue gas cooling generally adopts indirect water-cooling, indirect air-cooling and mixed cooling method. Indirect water-cooling adopts water-cooled tube; indirect air-cooling adopts powered air-cooling (plate type or tube type) and natural air-cooling; mixed cooling is to be mixed with flue gas from roof cover.

External exhaust consists of three methods of large sealed cover (dog house), semi-closed hood and roof cover. Now the guiding type roof cover is widely used, which is actually a combination of semi-closed hood and roof cover, collecting the advantages of semi-closed cover and roof cover, can completely collect the dust in the process of smelting, feeding and tapping of EAF.

2、The process flow of internal and external collecting system of EAF