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New energy
ProductSimultaneous desulfurization and denitrification of flue
1) Activated carbon method
The main equipment of the process is an activated carbon fluidized bed adsorber similar to an ultra-adsorption column in which SO2 in the flue gas is oxidized to SO3 and dissolved in water to produce a dilute sulfuric acid aerosol which is then adsorbed by activated carbon. Ammonia is injected into the adsorption tower, ammonia and NOx are formed into N2 under the catalytic reduction of activated carbon, and activated carbon adsorbed with SO2 can be heated and regenerated in the desorption device.
2) SNOx (WSA-SNOx) method
The WSA-SNOx process is a wet scrubbing and NOx removal technology. In this process, the flue gas first passes through the SCR reactor, NOx is reduced by the ammonia to N2 under the action of the catalyst, and then the flue gas enters the reformer, where the SO2 is oxidized to SO3 by the solid phase catalyst, and the SO3 is reheated by the flue gas. The GGH enters the WSA condenser and is converted to sulfuric acid by water absorption.
With SNOx technology, the removal rate of SO2 and NOx can reach 95%. The SNOx technology consumes no ammonia, does not consume other chemicals, does not produce secondary pollution such as waste water and waste generated by other wet desulfurization, and does not produce CO2 from limestone desulphurization. The inadequacy is greater energy consumption. The cost is high, and the storage and transportation of concentrated sulfuric acid are more difficult.
3) NOxSO method
A fluidized bed absorber (FB) is installed downstream of the electrostatic precipitator (EP), and γ-Al2O3 spheres impregnated with sodium sulfate are used as absorbents. After the absorber absorbs NOx and SO2, the reducing gas (CO) is used at a high temperature. , CH4, etc.) are reduced to generate H2S and N2.
4) High-energy particle ray method
The high-energy particle beam method includes an electron beam (EBA) process and a plasma process. The principle is to use high-energy particles (ion) to ionize some molecules in the flue gas to form active radicals and free electrons, and to oxidize NOx in the flue gas. This technology not only removes NOx and SO2 from flue gas, but also removes heavy metals and other substances at the same time.
The typical process includes: the generation of radicals, the desulfurization and denitration reaction, and the production of ammonium sulfate and ammonium nitrate. There are mainly electron beam irradiation technology and pulse corona plasma technology. Electron beam irradiation technology can achieve a denitrification rate of more than 75% without generating waste water and waste residue. Pulsed corona plasma technology can simultaneously desulfurize, denitrify, and remove dust, but it consumes more energy. At present, its reaction mechanism still lacks a comprehensive understanding.
5) Wet FGD plus metal chelate method
Zhong Zhaoping invented the jet bubbling method to use flue gas desulfurization and denitrification absorption liquid, including lime or limestone slurry, water-soluble organic acid accounting for 0.05% to 0.5% (mass fraction) of lime or limestone slurry and 0.03% of lime or limestone slurry. -0.3% (mass fraction) of iron or copper metal chelate. The disadvantage of the metal chelate process is that the recycling of chelates is more difficult because of the loss of chelates during the reaction, resulting in high operating costs.
6) Chloric acid oxidation
Due to the strong oxidizing property of chloric acid, the oxidizing solution containing chloric acid can be used for desulfurization and denitrification at the same time. The desulfurization rate can reach 98%, the denitrification rate can reach above 95%, and toxic trace metals such as As and Be can also be removed. Cd, Cr, Pb, Hg, and Se. In addition to chloric acid desulfurization and denitrification, the simultaneous removal of SO2 and NOx with NaClO3/NaOH also achieved better results.