Objectives
The HEG Limited, Mandideep is a leading manufacturer of graphite electrodes using CPC, Steric Acid and Iron Oxide as raw materials. HEG Mandideep plant is the third largest graphite electrode manufacturing facility in the world. The installed capacity of the plant was 60,000 MT with an annual turnover of about Rs. 600 crores.

The objective of the study at HEG Limited, Mandideep was to identify, prioritize, and recommend a set of cost-effective energy conservation schemes, which would reduce the overall consumption of electricity and fuel in the plant, without affecting the production or quality of products. Implementation of the suggested measures had led to reduction in the overall energy bill, thus reducing the cost of production and achieving a net increase in profitability.

The following equipment/systems were studied in detail in the energy audit:

• Compressed air system
• Water Pumping Systems and cooling towers
• Thermic Fluid Heaters
• Packaged Boilers (Steam Generation, Distribution & Utilization)
• Furnaces and Kilns
• Transformers
• Power factor and demand management
• Electric motors
• Fans
• Lighting

WII undertook field-visits to HEG Limited, Mandideep to collect the design and operating data and on-field measurement of energy-related parameters. The energy audit report coverered consolidated results of the following activities:

• A detailed analysis of the present consumption and past trends in fuel and electricity
• Preparation of the energy balance, estimation of heat/energy losses and operating efficiency of energy consuming equipment/areas
• Identification of a set of appropriate energy conservation schemes
• A techno-economic analysis of identified measures and prioritization of schemes for implementation. The economic analysis included cost of each intervention, achievable savings, and payback period. Based on the payback period, the schemes were categorized and prioritized under short-term, medium-term and long-term
• Implementation strategy measures identified
• A list of suggested equipment suppliers/manufacturers of energy saving equipment

It was found that there was a saving potential of around Rs. 3.1 crores per annum with one time investment of Rs. 1.1 crores having an attractive payback period of 5 months only.