Gujarat Ambuja - Redefining Operational Efficiency

<< Previous

Enhancing Productivity Contd...

GACL engineers found that by focusing on kiln operations, they could not only ensure cement quality, but could also reduce power consumption. A company official said, "You have to make sure that the reactivity is such in the burning zone that whatever you burn is converted into clinker3 minerals. And all this depends on the burning process, which we had no way of monitoring from the outside. Inadequate heating yielded inferior quality cement and over cooking made the clinker harder to grind." In the early 1990s, during a visit to a cement plant in Japan, GACL engineers learnt that factors like retention time (time elapsed in the kiln and the speed of burning), temperature, and rate of cooling could be judged from the microstructure of the clinker minerals. The Japanese engineers physically scanned the clinker pieces extracted from the kiln under a microscope to determine on the basis of their experience, whether the clinker had been heated to the right temperature. After undergoing extensive training, GACL's engineers tried the above procedure at their own plants and successfully brought down power costs from 120 units/ton to 90 units/ton.

At GACL's second plant in Ambuja Nagar, kiln productivity ranged between 2800-3000 tonnes. While setting up the third plant in the area, GACL engineers realized that if they had a larger pre-heater (in which the limestone was heated before being fed into the kiln), they would be able to put more material into the kiln and thereby increase production. However, the company's supplier of pre-heaters said it was not possible to make a bigger pre-heater without modifying the kiln. The engineers told the supplier to make a bigger pre-heater, while they themselves modified the existing kiln.

After spending two month studying the data available on kilns from the other plants, the engineers eventually worked out a plan for kiln modification. After the above plans were implemented, the same kiln began producing 3500 tonnes per day. With a marginal investment of Rs 24 million, the plant was now producing 0.17 million tonnes more per year.

Next >>

---

3] The raw materials for cement production, limestone, clay, silica and gypsum, are fed into a kiln after grinding and blending. The mixture is heated at 1300-1400 degrees for some time. After dehydration and calcination (removal of water vapor and carbon dioxide respectively), a dark and hard material is obtained, which is called clinker. This intermediate material is further processed with additional chemicals and materials and eventually ground into cement.