Particulate Conversion of SO2 by NH3 Injection in a Pulsed Corona Aerosol Reactor
Titel:
Particulate Conversion of SO2 by NH3 Injection in a Pulsed Corona Aerosol Reactor
Auteur:
Chang, Hyuksang Choi, Yuri
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 32 (2000) nr. 4 pagina's 268-283
Jaar:
2000-04-01
Inhoud:
Laboratory experiments were carried out to study the removal of SO 2 by the particle conversion process in a simulated flue gas condition. For the conversion of SO2 to particulate forms, NH3 was injected to the reaction zone. For the enhancement of particulate formation, a pulsed electric corona plasma was used. The behavior of particles formed in the different reaction conditions was studied. In the thermal reaction, the conversion from SO2 gas to particular sulfate was very sensitive to the reaction temperature. Once the molar ratios of NH3 to SO2 satisfy the stoichiometric ratio to form ammonium sulfate, [NH4] 2SO4, the additional supply of NH 3 to the reaction zone did not enhance the particular conversion rate of SO2 significantly. Instead the pulsed electric input enhanced the particular conversion rate of SO2 to the amount of increase by the additional NH3 injection. The experimental molar ratios of NH3 to SO2 were from 1 to 4. As the gas phase reaction between SO2 and NH3 had been completed within very short residence time, the final form of the particle size distribution was very dependent on the dynamic and or electrical factor in aerosol process that occurred down stream. The particle size distribution was measured using the EAA (Electrical Aerosol Analyzer) and the APS (Aerodynamic Particle Sizer) to estimate the aerosol process. Due to the long residence time in flow compared with the short residence in reaction, the aerosol found at the outlet of the reactor was well represented by a unimodal lognormal distribution. With the input of pulsed high voltage to the reactor, the reaction between NH3 and SO2 was enhanced by 20% compared with thermal reaction only, with an electrical energy input of below 1 kJ Nm3. The particulate conversion rate in the corona plasma reaction process was enhanced significantly by the oscillation of the mixing zone. The ranges of frequencies and electrical field strength were from 0 Hz to 1,500 Hz and from 0 kV cm to 50 kV cm, respectively.
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