About Steel re-Rolling Mill Steel Re-rolling is a major steel section and bar producing technology used in India and abroad. Since its inception in India with setting up of first re-rolling mill in Kanpur in 1928, this technology has contributed significant steelmaking capacity in secondary steel sector in India. Air Pollution Depending upon the fuel used in heating the furnace of a Steel Re-rolling Mill, the characteristics of flue gases may vary. For coal fired furnaces they may consist of gaseous as well as particulate pollutants. For oil or gas fired furnaces, these flue gases may consist of just gaseous pollutants. The flue gases may also be corrosive in nature. Selection of Technology for Air Pollution Control Device Selection of Technology for Equipment in an Air Pollution Control System in case of a Steel Re-rolling Mill depends upon the fuel to be used : a. Scrubber based System for Oil / Gas Fired Furnaces b. Cyclone and Scrubber based System for Coal Fired Furnaces About Scrubber based System for Oil / Gas Fired Furnaces Characteristics of Air Pollution Generated In Induction Furnace 1 Pollutants : Dust & Gases such as NO , SO , CO, Co x 2 2 2 Concentration : SPM - 1200-1500 mg/Nm (Maximum, in coal fired) 3 So - 800-1000 mg/Nm 2 4 NO - 20-50 mg/Nm x 5 Temperature : At Suction Point: 250-300 C 6 Nature of Dust : Slightly Sticky, Non Abrasive and Non Explosive Control Practices The control practice adopted in controlling air pollution in this industry mainly depends upon following parameters : 1 Dust/Gas Concentration at inlet 2 Discharge Standards 3 Temperature of Flue Gases 4 Nature of Pollutant i.e. Dust (Particulate) or Gaseous 5 Nature of Dust i.e. Sticky, Abrasive 6 Nature of Gases i.e. Corrosive, Non Corrosive Working of Equipment 1. Ducts & Bends : 2. Scrubber : 3. ID Fan : 4. Stack (Chimney) : About Cyclone and Scrubber based System for Coal Fired Furnace Working of Equipment 1. Ducts & Bends : 2. Cyclone : 3. Scrubber : 4. ID Fan : 5. Stack (Chimney) : Discharge Characteristics as Per Norms 1 Dust : Less than 150 mg/ Nm 2 Temp : Less than 80-100 C 3 Gases : Traces of SO , NO , Co , Co.