Denitrification method and system of cement rotary kiln

Abstract

The invention discloses a denitrification method and system of a cement rotary kiln. The method comprises the steps as follows: conveying fuel into a rising flue and / or a smoke chamber, conveying the fuel to the lower part and / or middle and / or upper part inside the lower section of a pyrolysis furnace, and conveying first tertiary air to the bottom and / or a lower conical part in the pyrolysis furnace; conveying second tertiary air to the middle and / or upper part inside the lower section of the pyrolysis furnace and / or the lower part inside the upper section of the pyrolysis furnace, conveying third tertiary air to the middle and / or the upper part inside the upper section of the pyrolysis furnace to enable the fuel to be burned in an oxygen lack state for generating a reducing agent. A part of NOx in smoke is reduced to a harmless substance by the action of the reducing agent in a reducing atmosphere zone, the fuel is prevented from generating NOx at the same time, and accordingly, emission concentration of NOx is effectively reduced. Meanwhile, combined with an SNCR denitrification technology and / or an SCR denitration technology, emission concentration of NOx is significantly reduced. The denitrification method and system have the advantages that travel of the smoke in the reducing atmosphere zone can be extended, denitrification efficiency is further improved, and denitrification cost of a cement enterprise is reduced.

Description

technical field [0001] The invention relates to a denitration method and a denitration system, in particular to a cement rotary kiln denitration method and system. Background technique [0002] (1) Nitrogen oxide NO in cement kiln system x The generation mechanism of [0003] ①Nitrogen oxides NO produced by raw materials and fuels x [0004] The raw materials and fuels used in cement production come from nature, which will inevitably contain a certain amount of organic matter and low-molecular nitrogen-containing compounds. Some of the nitrogen compounds in the raw materials are directly converted into nitrogen oxides NO x raw nitrogen oxide NO x , some of the nitrogen compounds in the fuel are directly converted into nitrogen oxides NO x Fuel Nitrogen Oxides NO x . [0005] The nitrogen in the raw material mainly comes from the nitrogen-containing compounds deposited in the ore, and its nitrogen content is generally 20-100ppm. [0006] Compared with thermal nitrogen...

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Problems solved by technology

[0033] Due to the short effective length of the reducing atmosphere zone in the prior art, the denitrification efficiency is only 20% to 30%.

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