Studying PGDS electric filters for removing high-ohmic magnesite dust

Conclusions Double-staged dust-extraction equipment based on NIIOGAZ cyclones of the type TsN-24 and electric filters PGDS-73-3 situated behind a rotary furnace (diameter 3.6 and length 90 m) for firing magnesite facilitated operations without a break in the health-safety norms for dust extraction.The optimum gas velocity in the cyclones in which their efficiency was about 90% is 7 m/sec. In this case there was no wear of the active part of the cyclones.The efficiency of the electric filter largely depends on the dust load on entry. With a reduction in the input dust concentration from 25.3 to 9.5 g/Nm³ the residual dust concentration is respectively reduced from 0.240 to 0.143 g/Nm³ with a water concentration in the raw material fed into the furnace of 1.2%.An increase in the moisture content of the raw materials to 2.5% causes a reduction in the resistivity of the dust from 10¹³ to 7·10¹¹ ·cm, and there is partial suppression of the back corona in the electric filter, as a result of which the residual dust concentration diminishes to 0.062 g/Nm³ which is less by a factor of 2 or more than the health-safety norms.Translated from Ogneupory, No. 7, pp. 18–25, July, 1970.