Increase in Cement Production by Increasing Dry Fly Ash Addition

Company details

Dalmia Cement (B) Ltd started cement production
operations in 1939 at Dalmiapuram.Then, the capacity of this Polysius plant was 250 TPD clinker production. Presently the total capacity is 4600 TPD of clinker production, due to continuous up gradation. How ever, still the old machinery of
1939 plant is in operation continuously.Dalmia cement manufactures a variety of cement Ordinary Portland cement (OPC), Portland Pozzolona Cement (PPC),OilWell Cement, Rapid Healing Cement etc.

Project Details

Fly ash is being used as a pozzolonic material for producing Portland Pozzolona Cement (PPC). This helps in material(Limestone, Clinker & Coke) conservation.
Previously out of the total fly ash addition, only 15% was dry fly ash. In the remaining wet flyash, the moisture content was as high as 25%. The higher moisture content has resulted in reduction of mill output.

In order to remove the moisture and increase the mill output the total heat requirement is about 14Mkcal/hr, out of which 11Mkcal is provided from the cooler vent and the remaining heat which is about 3Mkcal is provided by burning fuel.
The percentage dry fly ash addition was limited by the dry fly ash handling system.

Action taken

The plant team debated & brainstormed various aspects to identify and increase the utilization of fly ash.Various options including installing a new silo and a new fly ash handling system was one of the main aspects considered. How ever this scheme involved major capital investment & posed several layout related issues.The unit, how ever had some old raw meal silos which were a part of the earlier plant configuration. This silo did not have any role in the modernized unit & hence the plant team decided to use this idle capacity available for storing fly ash.
Using the pneumatic conveying system the dry fly ash from silo is transported to intermediate hopper. From the hopper the dry fly ash is fed to the mill feed chute in a controlled manner.
This resulted in increasing the dry fly ash addition from 15 to
40%, resulting in both electrical and thermal energy savings.

Results of the project

1.Electrical power savings of about 3,60,000 kWh,equivalent to a monetary saving of Rs 1.5 million
2.Coal saving of about 793 tons, amounting to about Rs 2.84 million
3.Total saving of Rs 4.34 million per annum
4.Reduction in fugitive emissions.

via Green business center