Cement, Energy and Environment

Review of the Electrical System Losses o Losses related to power generation, transmission and distribution o Mechanical losses of the rotating equipment o Losses caused by the failure of the protective relays and switchgear to get energy audit carried out by accredited energy auditors and to comply with the norms of specific energy consumption. In this context, the specific power consumption in kwh/ton (metric) available from UNIDO for 43- grade cement can be used as a norm for benchmarking. o To use elevator for kiln feed transport in place of air-lift o To use blowers for packing department in place of compressors o To use roll- press prior to cement grinding mill. It saves 10-15 % power. 0 A vertical roller mill consumes about 30 o Corona losses in EHV Operating Areas kwh/ton % less power than voltage levels o Miscellaneous other losses e.g. poor earthing, overloading etc. Steps to Reduce Losses o Crushing and stacking o Reclaiming, transport, grinding o Kiln feed, kiln, cooler o Coal mill 0 Cement- grinding, transport o Packing plant o Lighting, services, pumps etc 1.5 18.0 22.0 5.0 23.0 1.5 4.0 the ball mill; it can be employed for coal grinding, limestone grinding and recently introduced for cement grinding also. 0 To use electronic chokes in place of conventional ones. o Use of photoelectric or light dependent resistors (LOR) for indoor and outdoor lighting controls. Total 75.0 ~ 0 To use timer controllers where 0 Providing line post sensors in HT (High Tension) and LT (Low Tension) lines for fault detection o Installation of load flow controllers with static transfer switches. o By using computer aided software e.g. SCADA (Supervisory Control and Data Acquisition System), energy management software etc. Power Consumption Profile of A Cement Plant: Cement manufacturing is a power-intensive process, where about 40% of the cost is spent on energy. It offers a great potential for conservation by introducing energy audit. In compliance to the Energy Conservation Act of 2001 , it is mandatory for the designated consumers of electrical energy (Source- UN/DO) In order to meet these figures of specific power consumption and to make efforts for the energy conservation program, the suggested areas of action are summarized as follows. 0 To interlock the crusher auxiliaries to minimize idle running 0 To introduce closed circuit grinding, using high efficiency separators in grinding mills o To use variable speed drive motor e.g. VFDs for fans in pre-heater, ESP, Cooler etc. and to eliminate the use of damper control, where possible. o To replace compressed air by mechanical conveying for transport of cement to silo. possible. o To use 36W slim tubes for lighting. o To explore the use of BLOC and VFD motors for power conservation o To consider providing a single stack or a common exhaust on a building , where more than one fan or one machine units are installed and each having a exhaust fan. References o Energy Conservation in Induction Motors by Technology Trends Nov. 2001. o Determining Electric Motor Load and Efficiency by Dept. of Energy, USA. 32 ' ..._