Product Description
Brief introduction of H2O2 oxidative denitration technology
As the main component of nitrogen oxides in flue gas, NO and NO2 have significant differences in properties. NO2 has greater solubility in water, and the nitric acid and nitrous acid generated after dissolution can react with common desulfurization absorbents (such as CaO, Na2CO3, etc.). Not only does NO have very little solubility in water, but it cannot react with common alkaline absorbents. Therefore, NO can be oxidized to NO2 and higher-order oxides by oxidation technology, and then absorbed by an absorbent.
Hydrogen peroxide (H2O2) is a substance with strong oxidizing properties. It is often used as a disinfectant. At a certain temperature, it can oxidize insoluble NO in flue gas into water-soluble NO2, N2O3, N2O4, N2O5 and other high-valent states The main reaction equation of nitrogen oxide and H2O2 oxidation of NO is:
H2O2 → 2OH
H2O2 → HO2 + H
OH + NO → NO2 + H
HO2 + NO → NO2 + OH
The main side reactions of H2O2 are:
H2O2 → H2O + 1 / 2O2
The oxidized NOX mixture with a high degree of oxidation reacts with the alkaline absorbent in the wet scrubber to form salts for removal. Reaction equation between H2O2 and alkaline absorbent (using Na2CO3 as an example)
The formula is as follows:
Na2CO3 + 2NO2 → NaNO3 + NaNO2 + CO2
Na2CO3 + NO + 2NO2 → 2NaNO3 + CO2
Soluble NOX is absorbed by the wet scrubber to produce nitrite, nitrate and sulfate.
5. Process flow and configuration of H2O2 oxidative denitrification system
H2O2-based oxidation absorption denitration system consists of storage system, conveying system, distribution system, injection reaction system, compressed air system, electrical and control system. Craftsmanship
The flow chart is shown in Figure 4-1.
The most critical part of this process is to suppress the unnecessary decomposition side reaction of H2O2 at high temperature, and to achieve rapid and uniform mixing with the flue gas under the spray of the special nozzle to achieve the NO
Full and rapid oxidation to meet the removal efficiency of NOx at higher concentrations. The fully oxidized flue gas enters the wet scrubber for purification and absorption, and SO2 and NOx are simultaneously absorbed and generated
Sulfate, sulfite, nitrate and nitrite.
6. Process system characteristics
The denitration process is advanced, with no secondary pollution, low investment cost, simple operation and small footprint, combined with wet scrubbing method can effectively remove NOx (NO and NO2).
1) Compared with SNCR, the required reaction temperature is lower, the ejector is easy to install, and is not limited by the structure of the boiler body.
2) The denitration efficiency is medium, which can meet the higher NOX control requirements.
3) The reaction of H2O2 and pollutants is a homogeneous gas phase reaction, and the reaction is rapid.
4) It can be combined with the wet desulfurization scrubber used by most boilers to absorb oxidation products, reducing equipment investment.
5) H2O2 denitration equipment is installed in a modular structure. The furnace shutdown time required for installation is extremely short (2-3 hours), which does not affect normal production.
