Pollution control and energy conservation are inter-related in brick kilns.
The combination of energy saving and reduction in pollution is a win-win situation for everyone with saving in energy costs and better working conditions for kiln workers and operators and reduction in pollution and conservation of energy resources for the society in general. But this can only happen if the pollution control packages and energy efficient operations are sincerely followed. New approach to operational practices requires a paradigm shift, integrating the whole process innovations with new patterns of technology designs. The technology innovations and trained human resources are a valuable asset, but the advantage of all this can only be taken if the work force is ready to change its mindset. All this requires training in improved technology options.
In 1857, a continuous brick kiln was invented by F.E. Hoffmann in Germany. The first kiln had a circular,
arched tunnel surrounding the chimney. This reduced the fuel consumption by more than 50% compared to periodic
Thirty years later in 1887, a British engineer W.E. Bulls designed an arch-less version of the Hoffmann
kiln which is now called the Bull’s Trench Kiln or BTK. Its greatest advantage is its low cost of construction and comparatively
low energy consumption. This type of kiln is most widely used in Asian countries of India, Nepal, Bangladesh, Pakistan, Afghanistan and Myanmar.
Due to its proliferation and popularity in India efforts to reduce environmental emissions were taken up. The major contributor in this research and development activity was the Central Building Research Institute (CBRI),
Roorkee. The efforts mainly looked at introducing incremental changes in technical details and firing practices to improve operational efficiencies. These improved practices were also endorsed by the Ministry of Environment and Forests, Government of India through Gazette notification.
FCK in operation
One of the major changes in the kiln structure was the introduction of “gravity settling chambers”. Gravity settling chamber is a civil construction incorporated along the length of the kiln on both sides of the chimney. It is constructed at the base of the chimney connecting to all the flue inlets. The construction of the gravity settling chamber consists of baffles to obstruct the flue gases and lengthen the residence time of the flue gases. This results in deposition of the particulate matter in the settling chamber thereby reducing the ambient air emission. Introduction of gravity settling chamber reduces pollution, with no positive effect on energy consumption.
Some of the improved practices being promoted by various organisations such as Central Building Research Institute (CBRI), Roorkee; Punjab State Council for Science and Technology (PSCST), Chandigarh; Aligarh Muslim University (AMU), Aligarh; Technology and Action for Rural Advancement (TARA), New Delhi, are in the areas of better feeding, firing and operating practices. These are not country specific and can be adopted across regions.
Selective innovations in the FCK
• Use of energy saving additives
• Improved storage of coal
• Reduced size of coal
• Smaller size of spoon used for coal feeding
• Zig-Zag feeding pattern
• Reduced feeding interval
• Higher chimney height
• Better air flow and supply through changes in brick setting pattern
• Increased combustion zone
• Efficient use of damper and its operation
• Arresting heat losses through simple measures
• Pattern of stacking in curves
• Changes in brick setting to improve efficiencies
• Flue damper insulation
• Insulated feed hole cover
All the above individually will not result in any significant changes in energy consumption and environmental emissions. However, when worked in unison will achieve the desired results.