There are primarily two advantages that can accrue to a brick entrepreneur when a Fixed Chimney Bull’s Trench Kiln (FCBTK) is converted into a Zigzag Kiln.
In addition, there is reduction in air pollution, which helps in meeting air pollution regulations and reducing adverse environmental impacts.
On an average, a properly constructed and properly operated Zigzag Kiln saves 20%-30% fuel as compared to an FCBTK. For a kiln producing 50 lakh bricks per year, the annual savings in coal could range from 150–200 tonnes per year or an annual savings of Rs 7.5 lakh to Rs 20 lakh.
Typically, only 50%-60% of the bricks produced in an FCBTK get classified as Class-1 bricks. On the other hand, 80%-90% of the bricks produced in a Zigzag Kiln can be classified as Class-1 bricks. For a kiln producing 50 lakh bricks per year, this means an additional 10-15 lakh Class-1 bricks. Class-1 bricks get higher price in the market and are easier to sell.
Typically, SPM emissions from FCBTKs are in the range of 150–1250 mg/Nm3, while SPM emissions from Zigzag Kilns are in the range of 30–250 mg/Nm3. There is a visible difference in the colour of smoke. While the colour of smoke in an FCBTK is often black, the smoke from a properly constructed and operated Zigzag Kiln is light grey in colour.