Cement Energy and Environment

2.2. Thermal Audit Unit 1: Heat balance was carried out when the kiln was operating in stabilized conditions at 6702 TPD (279.25tph) clinker output and the specific thermal energy consumption for unit was 756 kcal/kg clinker. Unit 2: Heat balance of the kiln was carried out when it was operating in stabilized conditions at 7318 TPD (304.8tph) clinker output and the specific thermal energy consumption for unit was 712 kcal/kg clinker. Based on the results of thermal audit of both the units factors for high heat consumption for unit 1 & 2 were identified and corrective actions taken to improve thermal energy consumption. The summary of achievement is given below: Reducing preheater exit gas temperature to around 300 °C from above 320 °C for Unit 1. 2. Optimization of cooler performance for improving thermal recuperation efficiency of Unit 1 & Unit 2 coolers to above 60% from the existing levels of 51 % for Unit 1 & 55% for Unit2 resulting in thermal saving to the tune of 25 kcal/kg of clinker. 3. Reducing Bond's work Index of clinker from 17.5 to 15 kWh/t for Unit 2 by kiln optimization thereby reducing cement grinding power consumption. 2.3. Electrical Audit Based on the audit carried out and discussions with plant team, major factors for increased power consumption and power cost identified are given as under: 4. Inability to avail peak hour advantage due to improper load management. 5. Use of over capacity fans and compressors resulting in losses. 6. High Bond's Work index of raw material and clinker resulting in increased power consumption in grinding of raw material & clinker. Action plan was initiated by the plant considering the above findings. The following steps were adopted: a) Identification of the transformers with high losses for taking corrective action. b) Check the slow runs. c) Optimization of start up/ramp up plan during any stoppage. d) Availing peak hour discount with implementation of action plan for optimum power cost as per power tariff. e) Operating the compressors, water pumps and fans as per the desired specification and usage. Following measures have been implemented/under implementation conceptually for reduction in power consumption: 2.3.1. Distribution Transformers Load Rationalisation: Load on all distribution transformers has been studied for rationalisation. After detailed study 6 transformers were switched off in entire plant, which has reduced losses - 35 kW. 2.3.2. Utilities Load Optimisation: 1. Transformers losses are about 0.5 - 0.8%. HT ~ Review of plant area illumination with Lux motors losses are in the range of 4-5% and LT motors losses were found to be 10%. 2. Slow runs and output losses contribute 3-5% losses in overall electrical energy consumption. 3. Delayed start up, sequence and timing of start and stop is another factor for increased power consumption. In short if the Overall Equipment Efficiency (OEE) is less than 85% the losses could be more than anticipated during the linear ambition. meter and provision of on-off switches at accessible points, which user can operate as per requirement. );> Regular monitoring of compressors, water pumps, HVAC and other miscellaneous consumptions, to reduce losses in power consumption. );> Utilities consumption reduced from 697701 kWh in January 2015 to 465837 kWh in April 2015 due to adoption of proper measures.