- PK Ghosh, Group Managing Director, Ercom Engineers Pvt Ltd
What is the unit per tonne of energy consumption consumption in a cement plant in India?
The average electrical energy consumption in India is around 90-95 kWh/tonne cement (OPC) whereas the best achievement is around 80 kWh/tonne cement (OPC). Similarly, average thermal energy consumption is around 760 kcal/kg clinker, whereas the best figures achieved are around 680 kcal/ kg clinker. There is scope for reduction in both thermal and electrical energy consumption in many of the cement plants in India.
The contribution of the various departments to power and heat consumption is given in the Table-1 (refer this table in the page 31).
The best achievable figures are generally observed for the larger scale plants in India using the state of the art technology when operating at or higher than design levels.
What are the factors affecting Energy efficiency? What steps/ operational measures you have initiated to achieve the target - for both thermal and electrical energy optimisation?
The energy performance of cement manufacturing units is dependent on the following factors:
a. The age and type of the manufacturing technology such as:
i. Number of preheater stages
ii. Presence and type of calciner
iii. Type of cooler
iv. Type of raw mill grinding system and the separator
v. Type of cement grinding system and presence of pregrinders
vi. Auxiliary material transport systems
b. Cement product type such as OPC, PSC or PPC
c. Capacity utilisation
The energy efficiency achieved is the result of optimization between capital expenditure and reducing operating expenses.
In case of specific heat consumption, approximately 20 per cent losses are through preheater exhaust gases, 12 per cent are through cooler exhaust gases and around 4-5 per cent are radiation losses (for 6 stage preheater - precalciner system with the state-of-the-art cooler).
These losses may be reduced by: