Development of Pollution Control Technology During Coal Combustion - Simultaneous Multi-Pollutants Removal in Flue Gas by Ozone - page 4

operation, no fouling and plugging, and easy handling of solid products. Moreover,
this technology seems to be more economical and efficient in retrofitting the
existing power plants than WFGD.
1.2.1.4 Calcium Injection/Humidification Desulfurization Technology in
Furnace
Limestone, dolomite, and hydrated lime are typically used as desulfurizers, which
are decomposed into CaO for SO 2 absorption [11] . The Alanco Company in the
United States provides a charged spray dry absorbent device for dust removal and
desulfurization system [12] . This device allows a high-speed absorbent flow
through a high-voltage electrostatic-corona charging zone generated by the spray
unit, so that the absorber carries strong electrostatic charge. As the absorber flows
into the sooty flue gas, the electrical charges will exclude the particles with each
another. Therefore, a uniform distribution with suspended state is then formed to
produce a sufficient reaction between the absorbent and SO 2 . This technology
approves lower investment and small space needed, and is suitable for retrofitting
old plants. However, the high technical demands and complex maintenance of this
technology limit its application.
1.2.1.5 Electron-Beam (E-Beam) FGD Technology
The e-beam FGD technology is adopted for injecting NH 3 into flue gas, which is
then irradiated by e-beam [13,14] . Therefore, SO x and NO x in flue gas react with
NH 3 to generate (NH 4 ) 2 SO 4 and NH 4 NO 3 . This desulfurization technology is
competitive and has the following main features: (i) It is simple and can realize
desulfurization and denitrification efficiently and simultaneously; (ii) The entire
desulfurization process does not require post-treatment of wastewater; (iii)
(NH 4 ) 2 SO 4 and NH 4 NO 3 , which are the by-products of the reaction, are considered
as raw materials of compound fertilizer production; (iv) This technology occupies
small space and is a good alternative either for retrofitting old plants or
newly-built units; (v) After treatment, flue gas can be directly released into the
atmosphere; (vi) It requires relatively lower investment and operation cost.
1.2.1.6 Seawater FGD Technology
Seawater is commonly used as desulfurization agent for absorbing SO 2 through