What are the Different Kiln Technologies?
Brick making is an ancient technology with many of the kiln technologies available today being the same as they were thousands of years ago.
The following table summarises the kilns currently used around the world:
|An ancient primitive 4000 BC technology. This kiln is highly polluting, inefficient fuel use and labour intensive. Widely used in Asia, Latin America, Africa. Operate only in intermittent mode. HZZK replaced the South African Clamp kiln with a clean brick firing technology which brought an 82% fuel saving as compared to the South African Clamp Kiln. Clamp Kilns are banned in many countries as they are uneconomical, appallingly polluting with hazardous working conditions.
|Invented in Germany 1858. Also known as Hybrid Hoffman or Fixed Chimney Kiln. Designed with large, permanent masonry arches and expensive tall chimney approx. 30 metres tall. Kiln must operate in continuous mode.
|Bull’s Trench Kiln – Movable Metal Chimney
|Invented in England in 1876. Workers move hot metal chimneys as the fire moves through the kiln. There are very high emissions and hazardous working conditions. Now generally banned though has been commonly used in Afghanistan, India and across developing South Asian nations.
|Fixed Chimney Bulls Trench Kiln (FCBTK)
|Prevalent in South Asia with an estimated 70% of India’s kilns (FCBTK). Also common in Bangladesh, Pakistan and Nepal where pressure for low emission technology is mounting, due to highly polluted air and related health concerns. The FCBTK has a tall, expensive 30 metre brick chimney and is highly polluting. Used in the ‘dry’ season only. Operates only in continuous mode.
|Invented in Germany in 1877. Bricks move mechanically and continuously through a long stationary fire zone. Highly mechanized and automated processes, expensive to construct, requires highly skilled workers, dependent on a reliable electricity supply.
|Vertical Shaft Brick Kiln (VSBK)
|Invented in China 1958. Introduced into Asia early 1970’s. Has a limited production output and is very ‘clay specific’. Working conditions, arduous and hazardous.