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Method of eliminating NOx in metallurgy sintering process

A sintering process and removal technology, which is applied in the removal of NOx in the metallurgical sintering process and the field of NOx removal in the iron ore sintering process, can solve the problems of high energy consumption and low utilization efficiency of volatile matter in the sintering process, and achieve reduction Concentration, reduction of NOx emissions, low investment effect

Inactive Publication Date: 2007-09-12
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
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  • Description
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Problems solved by technology

In addition to the sensible heat of sintering ore and the sensible heat of sintering flue gas being almost useless, another main reason for the high energy consumption of the sintering process is that when the coal is directly burned, it produces pyrolysis gas (coal gas) and carbon black, etc. Gas is discharged, so the utilization efficiency of volatile matter in coal is low

Method used

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  • Method of eliminating NOx in metallurgy sintering process
  • Method of eliminating NOx in metallurgy sintering process
  • Method of eliminating NOx in metallurgy sintering process

Examples

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Effect test

example 1

[0024] In a small vertical Al 2 o 3 In a straight tube heating furnace, under an inert atmosphere, the single-component gas in the simulated coal gas reduces the NO in the sintering tail gas, and the N 2 The mixed gas of NO and NO simulates the sintering tail gas. The total gas flow rate is 2.5L / min, the concentration of NO is 300ppm, and the gas single-component H 2 , CO and NH 3 The concentration of NO is 0.3%. The heating process of the heating furnace is controlled by the temperature controller, and the concentration of NO in the gas is detected online by the flue gas analyzer. Three gases reduced NO to N when the temperature was raised to 1000 °C in a simulated heating furnace 2 The conversion rates were: 93.5%, 41.7% and 90.3%. When the reaction temperature is kept constant at 1000°C, the concentration of CO is increased to 3.0%, and NO is converted into N 2 The conversion rate can reach 80.8%.

example 2

[0026] To simulate the distribution of coke during the sintering process, mix 5g of coke and 50g of alumina pellets evenly and place them in a vertical Al 2 o 3 In the middle of the constant temperature zone of the straight tube heating furnace, the temperature is programmed for heating, and N 2 As a protective gas, when the temperature of the material layer reaches 800°C, switch between air, air and CO mixture or air and H 2 Mixed gas, the total gas flow is 4.0L / min, CO and H 2 The concentration is 2.0%. The result of the reaction is shown in FIG. 2 . In the process of coke combustion, reducing gas H is introduced 2 and CO can effectively reduce NO x The emission concentration of CO2 is more obvious.

example 3

[0028] In a small vertical Al 2 o 3 In the straight tube heating furnace, a certain amount of sintered ore (10 cm in height) is loaded, and the mixed gas of air and NO is used to simulate the returning sintering tail gas, and the NO x The concentration is 300ppm. Heating by temperature programming, CO and H were respectively introduced during the heating process. 2 , to examine the effect of temperature on H 2 and CO to remove NO from combustion tail gas x impact of changes. The flow rate of air is 2.5L / min, CO and H 2 The concentration is 2.0%, under the action of sinter, H 2 and CO removal back to NO in the burnt tail gas x The change law with the reaction temperature is shown in Fig. 3.

[0029] It can be seen from Figure 3 that the sintering tail gas is returned to the sintering process, so that the sintering tail gas passes through the sinter layer, and in the temperature range of about 500 °C, H 2 and CO can convert the NO in the combustion tail gas x The conce...

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Abstract

The invention relates to a method for removing NOx during a sintering process. In the invention, it adds coke powder or semi-coke powder as fuel in the ingredients, and it connects to gas during sintering process, meanwhile, it returns 10%~50% of the sintered exhaust to the sintering process, and it uses the reducing gas (H2, CH4, and CO)of gas, precursor (NHi and HCN) of NOx and coke to reduce the NOx of the sintered exhaust and NOx of the combustion of coke to N2, thereby it reduces the density of NOx in the exhaust gas.

Description

technical field [0001] The invention belongs to the field of metallurgical environmental protection, in particular to a method for removing NO in the process of metallurgical sintering x The method is suitable for NO in the iron ore sintering process of iron and steel enterprises x removal. Background technique [0002] At present, the annual NO produced by the sintering process of my country's iron and steel industry x About 1 million tons, accounting for the national NO x around 10% of total emissions. NO x It is easy to form acid rain, which affects the ecological environment and endangers human health. my country on SO 2 The emission limit is relatively strict, while the NO x The discharge restrictions of the country are relatively loose, which makes the type of acid rain in some areas of my country change from sulfuric acid to sulfuric acid-nitric acid mixed type and nitric acid type. If NO is not strictly controlled x It is difficult to achieve the ideal effect...

Claims

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Application Information

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IPC IPC(8): C22B1/16B01D53/56
Inventor 郭占成陈彦广王志
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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