Device and method for converting nitrogen oxide in flue gas into nitrite

Abstract

The invention discloses a device and method for converting nitrogen oxide in flue gas into nitrite and belongs to the field of environment-friendly waste gas treatment. The device comprises an ozone generator, a fan, a semi-oxidation device and an absorption tower. The ozone generator is connected to the semi-oxidation device through the fan, and the semi-oxidation device is connected to the absorption tower. According to the implementation way, part of NO in flue gas is oxidized to NO2, and then residual NO and NO2 generate nitrite easily absorbed by an absorbent under the spraying of spraying liquid. Small ozone generation amount and low investment and operation cost in the flue gas denitration process are achieved, NOx is converted into easily absorbed nitrite, and the discharged amount of the nitrite in circulating water is decreased.

Description

technical field [0001] The invention relates to the field of environmental engineering waste gas treatment, in particular to a device and method for converting nitrogen oxides in flue gas into nitrite. Background technique [0002] During the combustion process of thermal power plants, waste incineration plants, and cement plants, the NOx gas generated due to the oxidation of nitrogen has the characteristics of stimulating the human respiratory system, damaging animals and plants, destroying the ozone layer, causing greenhouse effect, acid rain, and photochemical reactions. Among them Most of them are NO, and it is extremely difficult to dissolve in water, which increases the difficulty of waste gas treatment. [0003] At present, the main technologies of flue gas denitrification are: selective catalytic reduction technology (SCR), selective non-catalytic reduction technology (SNCR), selective non-catalytic reduction technology combined with selective catalytic reduction tec...

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Problems solved by technology

Chlorine dioxide oxidation technology uses NaClO 2 / NaClO oxidizes NO, and then uses NaOH to absorb the residual acid gas. The denitrification efficiency is high, but the solvent consumption is large and the cost is expensive; the hydrogen peroxide oxidation technology uses hydrogen peroxide to oxidize NO, and then uses alkaline solution to absorb, and there is also a solvent The problem of high consumption and high cost; potassium permanganate oxidation technology adopts the method of absorbing NOx with alkaline potassium permanganate solution, which has high denitrification efficiency, and the content of KOH in the absorption liquid has an important influence on the removal of NOx, and the reduction of KOH is too large. It will soon restrict the strong oxidation ability of potassium permanganate and weaken the ability of potassium permanganate to oxidize NOx, thus reducing the treatment effect of exhaust gas

[0009] Ozone oxidation denitrification technology uses strong oxidant ozone to quickly oxidize NO in flue gas 2 , and then use the absorption liquid to absorb NO 2 , high denitrification efficiency, no catalyst poisoning, and complex process control problems, it is the most promising denitrification technology; the main problem at present is that, on the one hand, the ozone consumption is large, which increases the cost of denitrification; on the other hand, the NO 2 Substances converted into nitrates exist in the circulating fluid. Due to the difficulty in removing nitrates, nitrates are directly discharged into the sewage system, causing high ammonia nitrogen in the sewage and greatly polluting the environment.

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