Cement Energy and Environment

.. . c. For non-hazardous AFR, storage time is limited by the designed storage capacity. Storages for hazardous waste have to be specially designed to take into account their specific characteristics. Provisions for preventing and quenching fires will have to be made. Personnel handling fuel would have to use protective gloves and wear gas masks. Best thing would be that the storage of AF should be kept to a minimum inside the cement plant -just stock for a 6 to 7 days. In such a case however delivery would have to be regular, punctual and in required quantities. System design for liquid hazardous waste Liquid hazardous waste can be transported in drums and stored in covered sheds. Alternatively they can be received in tankers and stored in large tanks like regular fuel oil. Tanks may have to be provided with heaters for extraction and subsequent firing like in case of usual oil fired kilns. Liquid /gaseous fuels are generally conveyed in pipe lines and are extracted from tanks by means of pumps and fed to kiln . The firing feed rate is controlled by main fuel station for regulation of flow rate. A typical storage, handling and firing system for liquid hazardous waste is shown in figure 1 below: Unloading Storage Feeding ............................. .. ..... . . · ······················~···································~ .. .. .. .. .. .. .. == ~ •• • • .. .. Air . . .. . •••.•...•••...•.....•........ .....•.....••..... ...••..•.••......••....•.•..•...••...............•••••.• Figure 1: Liquid hazardous waste storage and firing system System design for Solid Hazardous waste Solid fuels need covered storage and handling facilities like that for additives in the cement plant. Solid alternate fuels storage can be managed manually by front end loader. But the flow rate specification of the installation is limited in manual loading. For managing higher flow rates efficiently automatic bridge crane system is needed. Fully automated grab crane system is best suited solution for efficient storage management with minimum storage space requirement and no manual intervention. Conveying of solid hazardous waste depends on fuel particle size, conveying distance, and location of fuel introduction to the system. Pneumatic conveying can be used for conveying fuels of fine particle size and for larger particle size mechanical conveying is generally used. Weigh feeders/vibro feeders are used for feeding solid hazardous waste depending upon type of fuel. If hazardous wastes are to be fired in the calciner, a double flap gate is requ ired for arresting false air entry into the system. A typical storage, handl ing and firing system for coarse solid hazardous waste is shown in figure 2 below: 15