Cement, Energy and Environment

32 with “Horse Shoe” refractory and for optimal clinker distribution on the static grate with high specific cooling air to achieve the benefits of Highest recuperation efficiency, Excellent clinker distribution across cooler width, minimum “Snowman“ formation and Low clinker temperature at beginning of moving grate. For the cooling zone section, low maintenance-high efficiency grate plates are being offered. The salient features of these patented plates are autogenous wear protection and reduced pressure drop due to optimally designed aeration slots. 5.3 Radiation Losses: To arrest the radiation losses in the system KHD is doing proper insulation in the preheater and ducts along with special aluminum based paints to retain the heat within the system and increase the availability for intrinsic processes. 5.4 Stud Lining: On any grinding surface, lowest wear rates are achieved, if the ground material itself provides the wear protection. This is reached by profiling the surface in a way that it is partly covered with ground material. KHD’s patented STUD-Lining, consists of extremely wear resistant carbide cylinders inserted in the roller surface. More than 70% of the roller surface is covered with ground material, acting as autogenous wear protection. Wear rate of rollers/table in VRM is higher than Roller Press and this can be well attributed to the stud surfaces as offered by KHD. 5.5 Equipment Reliability: The detailed designing of the equipments play a critical role in the reliability of the equipment for e.g the cylindrical roller Bearing for the rollers due its shape and radial load carrying capacity doesn’t suffer skewing in the roller bearing housing and are easy for sealing and safer too. Similarly upside equipments like Rod Sizer, metal detector, magnetic separators are some of the equipments which are protecting and ensuring the long operating hours and smooth operation flow of the major equipments. This leads to nearly full time availability of the system throughout the year. 6.0 Implementation and Results Some of the plants supplied by KHD operate at Thermal and electrical energy level marked as best in Indian Cement Industry. One good and prominent example of Raw material grinding in Dalmia Cement wherein the arrangement for Roller Press is Comflex and the consumed Specific energy is only 10.5 kwh/t @ raw material at meters for fineness of 1.5% on 212. Similarly the energy consumed at Rajashree Cement Raw Material grinding where there are three Roller Press arrangement for output of 3 x 285 tph is 14.5kwh/t of raw material at meters and Power consumed till clinkerisation is only 50 kwh/t of clinker. KCP Cement is operating at 45 Kwh/ton (till clinkerisation) for consecutive last three years. Kiln lines at Rajashree Cement and KCP Cement are operating at thermal energy consumption of 685 Kcal /Kg Clinker. These are some of the few good examples of technologies implemented with the Energy Efficiency & Environment principle. Talking in terms of Cement grinding UTCL Dharni is operating at 21 Kwh/ton in PPC grinding with a roller Press and Ball Mill in semi finish mode. Latest advancements are the use of roller press in finish mode for the clinker grinding. Successful trials have been made and are ready for outputs. Since Slag is considered as an abrasive material machine reliability comes as important criteria for grinding. Also due to its high grindability and granulometry power consumption is a concern. KHD is operating with numerous roller presses for slag grinding for JSW Cement in an energy efficient manner. Currently one of the Roller Press System in JSW Cement is operating at 34 Kwh/ton for slag grinding at Blaine value of 4500. Similarly Birla Corp Durgapur is running at 26 kwh/t of slag at meters at output blaine of 4100cm2/gm. . These energy figures have set the norms in Indian Cement Industry for the lower energy consumptions and lower heat consumption using efficient technologies . Not only the Power and thermal consumption, KHD is having expertise to use alternate fuels either in Calciner or in Kiln. KHD is also supplying special “Combustion Chamber” for Municipal Waste and other difficult fuels to be used in Pyro-system. In fact Humboldt Wedag has supplied Handling and firing system for Municipal Waste to Vikram Cement for use of Jaipur City Waste and to Jaypee Cement to use Chandigarh City Waste. A conveying and firing system for rice husk, Shredded Tyre, coconut waste and agriculture waste has also been supplied to