Partition organization combustion self-denitration system with reduction furnace and decomposing furnace and process

Abstract

The invention discloses a partition organization combustion self-denitration system with a reduction furnace and a decomposing furnace and a process. The reduction furnace is arranged between a kiln tail smoke chamber and the decomposing furnace, an outlet of the reduction furnace is connected with the side face of the decomposing furnace, a tertiary air lower branch pipe is connected with the bottom of a decomposing furnace cone, and a transverse partition combustion environment of a central concentrated oxygen area and a peripheral light oxygen area is formed on the cross section of the decomposing furnace; a tertiary air upper branch pipe is connected with the middle of a decomposing furnace column, a strong reduction area is arranged in the reduction furnace, the space, below the tertiary air upper branch pipe, in the decomposing furnace is a weak reduction area, the space, above the tertiary air upper branch pipe, in the decomposing furnace is a burnout area, and a longitudinal gradient combustion environment combining the strong reduction area, the weak reduction area and the burnout area is formed. The transverse partition combustion environment is realized by longitudinallyand upwards feeding tertiary air from the center of the bottom of the decomposing furnace and tangentially rotating flue gas from the side surface of the decomposing furnace; the longitudinal gradient combustion environment is achieved through fuel graded feeding and tertiary air distribution. According to the system, partition organization combustion self-denitration is realized on the whole, and the self-denitration efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of flue gas denitrification in the cement industry, in particular to a zone-organized combustion self-denitration system and process with a reduction furnace and a decomposition furnace. Background technique [0002] The calciner is the key equipment in the cement production process. The main component of cement raw meal is calcium carbonate, and the carbonate in cement raw meal is decomposed into oxides in the calciner, which provides a basis for the subsequent clinker sintering reaction in the rotary kiln. Since the decomposition of carbonate needs to absorb a large amount of heat, a certain amount of fuel needs to be fed into the decomposition furnace to supply it. Generally speaking, the fuel in the calciner accounts for about 60% of the fuel consumption in the entire cement clinker calcination process. The combustion status of the fuel in the decomposition directly affects the product energy consumpti...

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Problems solved by technology

[0013] (1) In the existing linear calciner, the kiln gas enters directly from the bottom of the calciner. Even if the fuel is graded and burned, a reduction zone is formed at the cone of the calciner, which has a certain effect on reducing NOx in the flue gas from the kiln. However, due to The flue gas from the kiln enters the furnace directly, the space of the oxygen-poor combustion zone is limited, the residence time of the denitrification reaction is short, and the denitrification efficiency is generally about 30%.

[0014] (2) The fuel combustion rate of the existing calciner is limited by the temperature of the combustion zone and cannot be burned quickly. It is necessary to increase the volume of the calciner and prolong the combustion time to meet the demand for combustion. On the one hand, it increases investment and space occupation, and on the other hand Increased equipment surface heat dissipation energy consumption

[0015] (3) The temperature in the combustion zone of the calciner is limited by the crust on the furnace wall, which makes it difficult to further increase the temperature in the combustion zone in the existing technology

When the temperature in the combustion zone is too high, the raw material is prone to liquid phase at high temperature, resulting in skinning problems on the furnace wall

If the combustion temperature of the calciner is too high, it is easy to burn out the refractory material of the furnace wall

[0016] (4) The calciner fuel staged combustion method can only reduce the NOx produced in the rotary kiln, but cannot reduce the NOx produced by the combustion of the fuel itself in the calciner

Moreover, it is relatively difficult to ignite and ignite the fuel in the calciner, which is likely to cause fluctuations in working conditions and affect the stability of the cement production process.

[0017] (5) The method of gradient combustion in the existing calciner is limited to the interior of the calciner

Restricted by factors such as the volume of the calciner and the space of the site, the overall denitrification effect needs to be improved

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