Discharge Plasma For Flue Gas Desulfurization Reactor

The desulphurization and denitrification process by pulsed discharge plasma technology has been the recent research focus because of its advantages over traditional treatment methods for flue gas. But there are two main bottlenecks, the large scale pulsed high-voltage power and the energy efficiency, restraining the technology for industrial application. So the desulphurization process utilizing activated ammonia and water vapor by DC corona discharge and appropriate electrode configuration of pulsed discharge reactor are investigated. The factors influencing the ions' current and the number of OH radicals produced by DC corona discharge are investigated, and those influencing the desulphurization efficiency in the process of ammonia and water vapor activation are also studied, some useful data and parameters for designing a deSO2 reactor with the process of activated ammonia and water vapor are gained. Experimental study on electrode configuration and discharge characteristics of a pulsed discharge reactor is finished, and some useful information is gained.The main experimental conclusions gained are summarized below:1. In our experiments for measuring ions' current, ions' current produced by DC corona discharge increases with higher voltage; and ions' current in the air decreased half at the distance of 9cm to the activation electrode when the velocity of air is 0.5.2. The number of OH radicals produced by DC corona discharge has been measured utilizing the oxidation reaction between hydroxyl radicals and sulfur dioxide. In our experiments, when power infused into activation electrodes between 1.9W and 2.9W, vapor content and initial concentration of sulfur dioxide being 4.7%(w%) and 2000ppm respectively, the number of hydroxyl radicals detected is about 1015/cm3.3. The discharge characteristics of activation electrodes are influenced by diameter of needles, water vapor and ammonia. The corona current increases with thinner diameter and higher voltage, and ammonia and water vapor decreases the corona current.4. When using ammonia-activating process, the desulphurization efficiency is influenced by these factors, such as activation voltage, mol ratio(R) between SO2 and N3, ejection velocity of ammonia from needles, residence time and humidity of the flue gas. The desulphurization efficiency before and after activation increases with higher voltage, humidity, R and longer residence time; in our experiments, the appropriate ejection velocity of ammonia from needles is between 0.13m/s and 0.16m/s.5. When using water vapor activating process, the desulphurization efficiency is influenced by activation voltage, residence time of the flue gas, and flux of water vapor and diameter of discharge needles. The desulphurization efficiency increases with higher activation voltage and longer residence time; in our experiments, the deSO2 efficiency using discharge needles with inner diameter of 1mm is higher than that with inner diameter of 3mm; the deSO2 efficiency before activation increases with bigger flux of water vapor, when water vapor activated, the ejection velocity of vapor should exceed 3.54m/s.6. According to our experimental conclusions gained in previous chapters, a deSO2 reactor with flux of 20000Nm3/h of flue gas and initial concentration of 2000ppm using the process of simultaneously activated ammonia and water vapor by DC corona discharge is designed.7. The electrode configuration and discharge characteristics of a pulsed discharge deSO2 reactor are studied and some useful information is gained. In our experiments, When wire-to-wire spacing (b) and plate-to-plate spacing (d) satisfy the relation: b/d=0.4-0.6, primary streamer energy infused into the reactor was greater.