Low-carbon method for improving emission reduction efficiency of oxynitride in circulated flue gas from sintering machine

Abstract

The invention relates to a low-carbon method for improving the emission reduction efficiency of oxynitride in circulated flue gas from a sintering machine, and the method comprises the following steps: (1) taking the flue gas in the middle of the total flue gas from a main flue, circulating the taken flue gas, wherein the flue gas is specifically taken from the area 20-70% from the head of the sintering machine to the bottom of the sintering machine, and the content of the oxygen in the flue gas in the upper circulating hood of a sintering pallet is no less than 18%; and (2) uniformly allocating an iron ore into sintering auxiliaries to serve as a catalyst. The invention provides a technical method for improving the circular denitration for the flue gas from the sintering machine with lowcost and low energy consumption. The technical method is characterized in that the iron ore is uniformly added into the sintering auxiliaries based on the flue gas circulation of the sintering machine, so as to improve the efficiency for denitration of the oxynitride. The technology provided by the invention is implemented based on the flue gas circulation of the sintering machine, the efficiencyfor denitrating the oxynitride from the circulated flue gas can be increased to 80-90% on the premise of not increasing the investment on equipment and construction, and the cost for energy consumption and operation.

Description

technical field [0001] The invention relates to the emission reduction of nitrogen oxides (NOx) in sintering flue gas circulation, which meets the requirements of the national environmental protection policy, energy saving, emission reduction and low-carbon economy, and belongs to the technology for reducing the emission of nitrogen oxides in sintering flue gas in the field of iron and steel metallurgy. A low-carbon method for the emission reduction efficiency of nitrogen oxides in flue gas circulation of sintering machine. Background technique [0002] Sintering is an important process unit in steel production. A variety of air pollutants are produced during the sintering process, such as particulate matter, NOx, SO 2 , CO, HCl, HF, alkali metals, various heavy metals and various organic compounds including PCDD / F, etc. Sintering is the largest source of NOx emissions in iron and steel complexes. The NOx emissions of this unit account for 50% to 60% of the total emissions...

AI Technical Summary

Problems solved by technology

[0004] The flue gas composition of the sintering machine is complex and fluctuates greatly, and has the following characteristics: First, the flue gas volume is large, and the flue gas volume produced per ton of sintering ore is 3500-5000m 3 (working conditions); Second, the NOx concentration fluctuates greatly, and the concentration range is generally 150-700mg / Nm 3 The third is that the flue gas temperature of each bellows varies greatly, generally between 50°C and 400°C; the fourth is that the flue gas flow rate varies greatly, and the variation range can reach about 40%; the fifth is that the moisture content in the flue gas is large and unstable, generally 10 % to 13%; Sixth, the oxygen content is high, generally 13% to 19%; Seventh, the flue gas contains a variety of pollutants, except particulate matter, SO 2 , NOx, it also contains alkali metals, heavy metals, PCDD / F and many other organic substances; eighth, the average concentration of NOx in the total flue gas is low, generally 250-400mg / Nm 3 , which is far lower than the flue gas of the olefin coal boiler in the power plant, which is not conducive to improving the removal efficiency; Ninth, if the SCR process of the power plant is copied to the sintering machine, the cost of removing NOx per unit will be astonishingly high due to the consumption of catalyst and ammonia reducing agent

[0005] Sintering machine flue gas circulation deNOx can achieve negative energy consumption operation, but only 60% to 70% of NOx in the circulating flue gas can be removed

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