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CN-117654246-B - Reducing NO in sintering flue gasXMethod for discharging amount

CN117654246BCN 117654246 BCN117654246 BCN 117654246BCN-117654246-B

Abstract

The invention discloses a method for reducing NO X emission in sintering flue gas, which mainly solves the technical problem of high NO X emission in the existing sintering flue gas. The technical scheme is that the method for reducing the NO X emission in the sintering flue gas comprises 1) ore blending, wherein the mass percentages of the components of the sintering ore blending raw materials are 3% -8% of high-sulfur iron ore powder, 66% -75% of hematite rich ore powder, 4.0% -5.0% of solid fuel, 8% -15% of the sum of quicklime, dolomite and limestone, 5% -10% of sintering return ore, 2) evenly mixing and granulating, 3) air draft sintering, obtaining finished sintering ore after sintering, sampling and detecting the drum strength of the sintering ore and the sulfur content of the sintering ore, and 4) desulfurization and denitrification treatment of the sintering flue gas. According to the invention, the mass concentration of NOx in the sintering flue gas after the desulfurization and denitrification treatment by the cooperation of the circulating fluidized bed and the ozone is less than or equal to 35mg/m 3 ,SO 2 mass concentration and less than or equal to 5mg/m 3 .

Inventors

  • XIE CHAOHUI
  • HAN FENGGUANG
  • HUANG SHAOCHANG
  • ZHANG QING
  • QIU JINLONG

Assignees

  • 上海梅山钢铁股份有限公司

Dates

Publication Date
20260505
Application Date
20220831

Claims (4)

  1. 1. A method for reducing NOx emissions from sintering flue gas, said method comprising the steps of: 1) The ore blending and sintering ore blending raw materials comprise, by mass, 3% -8% of high-sulfur iron ore powder, 66% -75% of hematite rich ore powder, 4.0% -5.0% of solid fuel, 8% -15% of the sum of quicklime, dolomite and limestone, 5% -10% of sintered return ore, 100% of the sum of the mass percentages of the components, 1.80% -1.90% of binary basicity R 2 of the sintered ore, 1.40% -1.60% of MgO in the sintered ore, and 1% -5% of TFe 56% -62% of SiO 2 4％～8％,CaO 1％～2％,MgO 1％～3％,Al 2 O 3 %, and 1% -4% of S2% -4% of the sum of the other contents; 2) Mixing and granulating, namely placing the prepared sinter raw materials into a primary mixer for mixing uniformly, adding water and stirring to prepare a primary mixture, wherein the mass percent of H 2 O in the primary mixture is 6.4% -6.6%, placing the primary mixture into a secondary mixer for granulating, adding water and stirring to prepare a secondary mixture, and the mass percent of H 2 O in the secondary mixture is 6.7% -6.9%; 3) Exhausting and sintering, namely distributing the secondary mixture on a sintering trolley to perform exhausting and sintering, controlling the exhausting negative pressure to be 14-17 KPa and the ignition temperature to be 1050-1100 ℃ in the sintering process, and obtaining a finished product of sintered ore after the sintering is completed, and sampling and detecting the drum strength of the sintered ore and the sulfur content of the sintered ore; 4) The method comprises the steps of carrying out desulfurization and denitrification treatment on sintering flue gas, carrying out electric dust removal on the sintering flue gas through a machine head electric dust remover after the flue gas generated in the sintering process is pumped into a large flue, monitoring the concentration of SO 2 and NO X in the sintering flue gas before desulfurization and denitrification treatment on line after dust removal, then introducing ozone into the sintering flue gas after the machine head electric dust removal treatment, carrying out oxidation reaction on the ozone and NO in the sintering flue gas to convert the ozone into high-valence NO X , and then conveying the sintering flue gas after the ozone oxidation to an absorption tower through a pipeline for desulfurization and denitrification treatment, and monitoring the concentration of SO 2 and NO X in the sintering flue gas after the desulfurization and denitrification treatment on line.
  2. 2. The method for reducing NOx emission in sintering flue gas according to claim 1, wherein the mass percentage of the hematite rich powder component is TFe 60% -66%, siO 2 2％～8％,CaO 0.5％～2％,MgO 0.01％～2％,Al 2 O 3 0.1.1% -2%, S0.001% -1% and the sum of other contents is 1% -5%.
  3. 3. The method for reducing the emission amount of NOx in sintering flue gas according to claim 1, wherein the mass concentration of NOx in the sintering flue gas after the desulfurization and denitrification treatment by the cooperation of the circulating fluidized bed and ozone is less than or equal to 35mg/m 3 、SO 2 mg/m 3 .
  4. 4. The method for reducing the emission of NOx in sintering flue gas according to claim 1, wherein the mass percentage of S in the finished sinter is less than or equal to 0.020%, the drum strength of the sinter is 79% -82%, the sinter yield is 80% -82%, and the sintering utilization coefficient is 1.23-1.31 t/m 2 & h.

Description

Method for reducing NO X emission in sintering flue gas Technical Field The invention relates to a sintering flue gas control technology, in particular to a method for reducing NO X emission in sintering flue gas, and specifically relates to a method for reducing NO X emission in sintering flue gas through sintering ore blending and sintering flue gas desulfurization and denitrification, belonging to the technical field of ferrous metallurgy sintering ore blending and sintering flue gas treatment. Background Along with the promotion of ultra-low emission standard of sintering flue gas in the steel industry, the purification problem of pollutants in the sintering flue gas is needed to be solved. At present, the sintering flue gas desulfurization purification technology is very mature and can meet the emission standard, so that the sintering flue gas NO X becomes a primary pollutant of steel enterprises. Along with the continuous development and innovation of the flue gas denitration technology, the circulating fluidized bed and ozone integrated desulfurization and denitration technology is also applied to the sintering flue gas purification. More than 90% of the nitrogen oxides in the sintering flue gas exist in the form of NO, and the NO is indissolvable in water (the solubility is less than 0.1g/dm 3) and cannot be effectively absorbed by a desulfurization system. Higher solubility of NO X in water than NO, such as the solubilities of NO 2 and N 2O5 of 213/dm 3 and 500/dm 3, respectively, is easier to absorb. Therefore, NO which is difficult to be dissolved in water is oxidized into high-valence NO X which is easy to be dissolved in water through ozone, and then denitration is carried out by utilizing a follow-up circulating fluidized bed semi-dry desulfurization process. At present, measures such as controlling the carrying amount of nitrogen-containing organic matters in fuel, strictly controlling sintering process parameters, researching and developing NO X absorbing catalyst and the like are mainly adopted to reduce the emission concentration of NO X, but when the nitrogen oxide concentration of inlet flue gas exceeds 300mg/m 3, the denitration system cannot meet the environment-friendly requirement that the emission concentration of NO X is less than or equal to 35mg/m 3. Disclosure of Invention The invention aims to provide a method for reducing the emission amount of NO X in sintering flue gas, which mainly solves the technical problem of high emission amount of NO X in the existing sintering flue gas, and realizes that the emission concentration of NO X in the sintering flue gas is less than or equal to 35mg/m 3. The technical idea of the invention is that high-sulfur iron ore powder is mixed into a sintering mixture for exhausting sintering to produce sintered ore, sintering flue gas generated in the exhausting sintering process is subjected to head electric dust removal treatment, ozone is introduced, the ozone and NO in the sintering flue gas are subjected to oxidation reaction to be converted into high-valence NO X, the sintering flue gas is conveyed to a circulating fluidized bed semi-dry desulfurization system for desulfurization and denitrification treatment, sulfide in the sintering flue gas is converted into calcium sulfate and calcium sulfite after desulfurization treatment, nitride in the sintering flue gas is converted into calcium nitrate and calcium nitrite after denitrification treatment, and finally the sintering flue gas is purified and discharged. The technical scheme adopted by the invention is that the method for reducing the NO X emission in the sintering flue gas comprises the following steps: 1) The ore blending and sintering ore blending raw materials comprise, by mass, 3% -8% of high-sulfur iron ore powder, 66% -75% of hematite rich ore powder, 4.0% -5.0% of solid fuel, 8% -15% of the sum of quicklime, dolomite and limestone, 5% -10% of sintering return ore, 100% of the sum of the mass percentages of the components, and 1.80% -1.90% of binary basicity R 2 of the sintering ore and 1.40% -1.60% of MgO in the sintering ore; 2) Mixing and granulating, namely placing the prepared sinter raw materials into a primary mixer for mixing uniformly, adding water and stirring to prepare a primary mixture, wherein the mass percent of H 2 O in the primary mixture is 6.4% -6.6%, placing the primary mixture into a secondary mixer for granulating, adding water and stirring to prepare a secondary mixture, and the mass percent of H 2 O in the secondary mixture is 6.7% -6.9%; 3) Exhausting and sintering, namely distributing the secondary mixture on a sintering trolley to perform exhausting and sintering, controlling the exhausting negative pressure to be 14-17 KPa and the ignition temperature to be 1050-1100 ℃ in the sintering process, and obtaining a finished product of sintered ore after the sintering is completed, and sampling and detecting the drum strength of the sintered ore and the sulfu