A kind of high-concentration NOx flue gas denitration agent and preparation method thereof

Abstract

The invention provides a high-concentration NOx flue gas denitrification agent, which is made of raw materials including 100 parts of superfine ground calcium carbonate powder and 50-80 parts of ferrous sulfate heptahydrate in parts by mass; The mass content of the ingredients is CaCO 3 55‑70%, Fe 2 o 3 11‑17%, calcium sulfate 20‑28%, can be used at room temperature to 250 ℃, containing NOx30000 mg / m 3 The denitrification treatment of the following gases converts NOx absorption into Ca(NO 3 ) 2 and a small amount of Ca(NO 2 ) 2 , the denitrification capacity can reach more than 20% or even more than 30% of the mass of the denitrification agent before use; the denitrification agent does not expand during the denitrification process, the surface strength does not decrease, and the pulverization does not occur; the resistance of the denitrification agent bed does not increase. The agent is easy to unload and can be used as a nitrogenous fertilizer.

Description

technical field [0001] The invention belongs to the technical field of NOx-containing gas treatment, and in particular relates to a high-concentration NOx flue gas denitrification agent and a preparation method thereof. Background technique [0002] In the production process of many catalysts, purifiers and adsorbents, metal nitrates are often used as raw ingredients. The metal nitrate is decomposed in the subsequent kiln roasting process of the catalyst, purifying agent and adsorbent, and generates highly dispersed metal oxide active components in the catalyst, purifying agent and adsorbent, and releases NO-containing active components at the same time. 2 , NO, etc. are generally referred to as NOx nitrogen oxide gas flow, when NO 2 Concentrations over 2000 mg / m 3 When the gas is yellowish to brownish-red color, it generally needs to be absorbed by lye solution, acid urea solution and / or treatment liquid containing oxidant to eliminate its color, and it is possible to mee...

AI Technical Summary

Problems solved by technology

[0003] During the roasting process of the catalyst, purifying agent and adsorbent, the concentration of NOx in the kiln flue gas can sometimes reach 1% (volume) or even higher, and the fluctuation range is relatively large, and the gas flow is usually not large, generally every Dozens to hundreds of meters per hour 3 At the same time, the temperature is not high or low, such as 80-200°C, the main component is air, and it is discharged intermittently or for a short duration; therefore, the NOx-containing flue gas passes through lye, acid urea solution, and / or contains oxidant When the treatment liquid is circulated and absorbed, the scale of the absorption treatment device is small, the process and control are often not perfect, and it is inevitable that the exhaust gas of the absorption treatment does not meet the standard, and other disadvantages include: the investment is not low, the operating cost is high, and there are The problem of waste water and slag, the entrainment of the exhaust gas from the chimney to the final circulating absorption liquid, and the pollution of the surrounding environment caused by "falling snow"

The denitrification agent adopts CuO, Co 2 o 3 The cost of additives is also high, and the waste denitrification agent cannot be used and treated as farmland nitrogen fertilizer, because Cu and Co elements will cause soil pollution

[0005] The low-temperature flue gas denitrification agent of CN 110385023 A can be used for flue gas denitrification at 30-200°C, but only for low NOx concentrations such as 2000 mg / m 3 Denitrification below; when the NOx concentration in the flue gas is higher such as 3000 mg / m 3 Above, especially at 5000 mg / m 3 When the above conditions are above, the denitrification agent is prone to expansion, surface strength reduction and pulverization, resulting in an increase in the bed resistance of the denitrification agent and difficulty in unloading the waste agent after use, and the carbon powder contained in it is easy to ablate when used at a temperature above 200°C , resulting in a decline in the NOx removal accuracy and denitrification capacity of the denitrification agent