Cement Energy and Environment

Table 2 Modifications Carried Out and Benefits Accrued No• . "' Cooler and cllnker Gonveying system I. High stack emission in ESP installed in place of Noric dust cooler vent collector 2. High power consumption High efficiency fan installed 3. High cooler ESP vent gas Water spray system installed temperature which in the znd grate portion of cooler damaged electrodes and with auto-control in DCS reduced ESP efficiency (see Fig.! for details). 4. Fugitive dust emissions Dense-phase conveying system at transfer points of installed for transportation of clinker conveying system clinker dust from the cooler ESP hoppers to cement mill hoppers. 5. Low heat recuperation Retrofitted with IKN Kids efficiency, loss of thermal energy 11. Kiln bood, tertiary air (fA) dud and prec.aldner dud - Unit I 6 . The ·presence of bends at the take-off point from cooler and the gas entry point to kiln inlet riser duct resulted in frequent refractory failure in the bends and led to false air ingress into the system. Kiln hood modified with increased area and TA duct straightened to avoid bends. (This was carried out during the annual p lant shut-down of 45 days). 15 lefor-; modification Emission level 250 mg/Nm 3 60 mg/ Nm 3 Power consumption ,I 3kWh/tonne O.SkWh/ tonne cement cement Gas temperature 350-400° c 250-280° c Qust emissions Present Nil Cooler heat recuperation efficiency Low High Saving in thermal energy2.5 kcal/kg clinker. Kiln hood area 18.95m 2 24.73 m 2 Air velocity in hood 7,7 m/s 5.5 m/s Recirculation of clinker dust particles in cooler and TA duct High Low Ingress of false air into the system High Minimum Wear and tear of TA duct Very high Minimum Tertiary air temperature 650-750° c Maintenance cost Rs. 5 lac/ annum Rs. 1 lac/ annum