Flue gas denitration method and device by storing and reducing nitrogen oxides in circulating fluid bed

Abstract

The invention discloses a denitration method of the gas stored and reduced by nitrogen oxides of a circulation fluidized bed, which comprises the following steps: a. after being accelerated or pressured, the gas is directly sprayed into a storage reactor of the fluidized bed which uses a catalyst as a bed material to realize the oxidation, absorption and storage of NOx simultaneously when drivingthe bed material to flow; b. a gas-solid separator which is arranged at the tail of the storage reactor is used for realizing the separation of the gas from the solid; the gas phase can be directly discharged or can enter a later NOx purification system to be purified; and a solid catalyst enters a reduction and regeneration reactor of the fluidized bed; c. the catalyst storing NOx contacts with a reducing agent in the reduction and regeneration reactor of the fluidized bed to reduce the stored NOx and realize the regeneration of the catalyst; and d. the regenerated catalyst is introduced into the storage reactor of the fluidized bed. The denitration method is suitable for the gas denitration of a large flow, has high denitrification efficiency, low energy consumption, simple device structure and small occupied area, is easy to connect with the desulphurization device of the circulation fluidized bed for use, and has strong gas denitration adaptability.

Description

technical field [0001] The invention relates to a method for denitrification of flue gas by storage and reduction of nitrogen oxides, in particular to a method for denitrification of flue gas by storage and reduction of nitrogen oxides in a circulating fluidized bed, and also relates to a device for realizing the method. Background technique [0002] Nitrogen oxides (NOx) are one of the most important air pollutants. Excessive NOx in the atmosphere will lead to serious ecological and environmental problems such as acid rain, photochemical smog, and ozone layer destruction, which seriously restricts global sustainable development. Therefore, all countries in the world Strict standards have been set for NOx emissions. As my country's rapid economic development drives the rapid development of power, steel and other energy and resource industries, the problem of NOx emissions has become increasingly prominent. As the world's largest steel producer, my country's metallurgical si...

AI Technical Summary

Problems solved by technology

[0021] According to the working principle of NSR, this technology is expected to be used for flue gas denitrification, but none of the existing NSR technologies can meet the requirements of industrial flue gas denitrification. The main problems are as follows:

[0022] 1.) The existing NSR technology adopts the form of fixed bed in-situ reduction, and its operation method not only requires intermittent supply of reducing gas, but cannot meet the continuous operation requirements of flue gas denitrification;

[0023] 2.) The utilization rate of the reducing agent in the existing fixed-bed NSR technology is low, and a relatively large amount of reducing agent is still required in the in-situ reduction process. However, under the operating temperature and aerobic conditions of NSR in-situ reduction, the non-selective oxidation of the reducing agent lead to a large loss of reducing agent

[0024] 3.) The fixed bed operation process usually requires a higher reduction temperature, and the in-situ regeneration method poses challenges to the purification of large flow and low temperature flue gas;

[0025] 4.) The currently developed NOx trap catalysts are mainly noble metal catalysts, and the high catalyst cost is not suitable for flue gas purification

[0026] 5.) The current fixed bed flue gas catalytic denitrification process uses an integral catalyst, the pressure drop of the reactor is high, and catalyst regeneration and replacement are difficult, and the gravity of the fixed bed itself will squeeze the catalyst, and there is a danger of bed collapse. Conducive to long-term stable operation

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