Smoke circulation energy-saving tunnel kiln

Abstract

The invention discloses a flue gas circulation energy-saving tunnel kiln which comprises a preheating zone located on the side of a sealing door of the kiln head, a flue gas circulation zone located on the side of a sealing door of the kiln head and a flue gas circulation zone located on the upstream side of the flue gas circulation zone in sequence from the kiln head to the kiln tail. A fresh air inlet is formed in the downstream side of the firing zone; a circulating flue gas inlet is formed in the downstream side of the cooling zone; the hot air zone is located on the side of the kiln tail sealing door, a cold air inlet is formed in the downstream side of the hot air zone, and a hot air outlet is formed in the upstream side. According to the tunnel kiln, through the flue gas circulation heat exchange technology, the stricter environmental protection emission standard is met, one-time continuous firing can be conducted, the tunnel kiln has the advantages of being efficient and capable of saving energy, the product percent of pass can be effectively increased, and large-scale continuous production of green and red bricks and tiles is achieved.

Description

Technical field [0001] The invention involves tunnel kiln. More specifically, the present invention involves a type of flue gas cyclic capable tunnel kiln. Background technique [0002] As a continuous kiln, the tunnel kiln has the characteristics of short -burning time, high yield, good product quality, good labor conditions, and long service life of other types of kiln. Kiln, currently the production of red brick tile technology in tunnel kiln in China is mature, but there is still a large ventilation volume in the kiln, and the content of flue gas is generally higher than 17 %, resulting in a large amount of exhaust gas treatment, difficulty in environmental protection, and large energy consumption. [0003] The current tunnel kiln uses a single passage to cool and change heat with fresh air. All fresh air turns into flue gas after through the tunnel kiln. Direct emissions are discharged. In order to meet the heat exchange requirements, the ventilation volume is huge. At the s...

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Problems solved by technology

[0002] As a continuous kiln, the tunnel kiln has the characteristics of short firing time, high output, good product quality, good working conditions, and long continuous service life compared with other types of kilns. Kiln. At present, the tunnel kiln production technology in China is mature, but there is still a large amount of ventilation in the kiln, and the oxygen content of the flue gas is generally higher than 17%, resulting in a large amount of waste gas treatment, which is difficult to meet environmental protection standards and consumes a lot of energy.

[0003] The current tunnel kiln adopts a single channel to cool and exchange heat with fresh air. All the fresh air passes through the tunnel kiln and becomes flue gas, which is directly discharged. In order to meet the heat exchange requirements, the ventilation volume is huge, and the calcination in the kiln does not need to be so huge. This makes the oxygen content of the flue gas too high, and most of the air is directly discharged, which inevitably takes away most of the heat. At the same time, the huge amount of flue gas treatment also makes the flue gas treatment facilities of the tunnel kiln huge, and the investment increases. Large and not easy to meet environmental protection requirements

[0004] When firing blue bricks, the bricks and tiles that turn green after reduction and roasting must be cooled in an oxygen-free reducing atmosphere in order to prevent re-oxidation and redness. Until the kiln exit, the current tunnel kiln cannot achieve a reducing atmosphere in the cooling zone of the kiln due to the high excess coefficient of oxygen and air, and can only produce red bricks. Due to the limited means of anaerobic cooling in some tunnel kilns, it is difficult to achieve continuous production of green bricks and tiles

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