What are the two main categories of wet flue gas denitration technologies?
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What are the two main categories of wet flue gas denitration technologies?
1. SCR Selective Catalytic Reduction flue gas denitration technology； Under the action of metal catalysts (including precious and non-precious metals), ammonia is injected to reduce NOx in flue gases into nitrogen and water. The reducing agent is usually NH3, and an SCR reactor is required. Operating costs are greatly affected by catalyst life. 2. SNCR Selective Non-Catalytic Reduction flue gas denitration technology ； A reducing agent containing NHx groups is sprayed into the furnace at a temperature range of 800–1100°C; the reducing agent undergoes pyrolysis to produce NH3, which then reacts with NOx to form nitrogen gas. Using the furnace as a reactor requires modifications to the boiler. SNCR and SCR can be combined to use the ammonia released in the SNCR process to further react with NOx through SCR technology.
Chloric acid oxidation method, NaClO/NaOH method
Selective catalytic/non-catalytic reduction method, combined absorption method, electron beam irradiation method
Wet denitration relies on the oxidation, absorption, and separation process, but the water generated in this process is difficult to treat. The difference lies in the different absorbents.
There are SCR and SNCR; actually, there is also ESNCR. :lol
The main wet denitration technologies include: water absorption method, acid absorption method, alkali absorption method, oxidation-absorption method, absorption-reduction method, and liquid-phase complexation method. However, these methods are more suitable for treating exhaust gases from industrial processes and are not applicable to flue gases from coal combustion. The main dry denitration technologies include: Selective Catalytic Reduction (SCR), Selective Non-Catalytic Reduction (SNCR), Non-Selective Catalytic Reduction (NSCR), combined methods, electron beam irradiation, activated carbon oxidation (reduction), carbothermal reduction, ozone treatment, plasma therapy, and others. The selection is based on parameters such as flue gas volume, flue gas temperature, and concentration.
1； SCR requires a catalyst and involves high investment; 2. SNCR ； Ammonia spray ； Less investment