Study On Two Methods Of Flue Gas Desulphurization With Direct Current Corona Discharge

The technology of flue gas desulphurization (FGD) by using corona discharge plasma was deemed to be one of technologies with potential of study and development and application prospect. Considering the problem which FGD with pulse discharge plasma was confronted with, this dissertation studied two FGD methods that were negative direct current (DC) corona discharge cooperating with water absord and DC corona discharge injecting ammonia (NH3). The study was carried out for the sake of providing reference for FGD technology with DC corona discharge, which mainly investigated the relationship between the the two methods' desulphurization effect and influencing factors, and discussed the experimental results. The research results as follows:(1) There was a synergistic effect for FGD when combining negative DC corona discharge with water absord, which improved desulphurization effect. The efficiency of desulphurization with water absord or corona discharge only was much lower than that by combining them. This synergistic effect made the quantity of acid radical ion componentschanged and the concentration of sulfate ion (SO₄^2-) increase. The efficiency can also beimproved when flue gas was sent into the reactor from the center of high voltage electrode, because that made flue gas processed entirely by corona discharge. Moreover, the efficiency increased when voltage increased and exposure duration got longer. More than 90% of the efficiency can be obtained under these conditions: flue gas flux 0.1Nm³/h, flue gas exposure duration 7s, voltage 13kV and SO₂ initial concentration about 430×10^-6. The energy consumed was about 3Wh per 1Nm³ flue gas.(2) DC corona discharge injecting NH3 had good effect of FGD. Higher voltage, longer exposure duration and bigger mol ratio was propitious for efficiency increasing. Efficiency above 80% can be obtained when flue gas flux was 15Nm³/h, SO₂ initial concentration was about 1500×10^-6, flue gas temperature was about 70℃, vapor content was about 7.5%, the mol ratio of NH₃/SO₂ was 2:1 and positive power was applied. In the same time, its energy efficiency was 3.5Wh/Nm³.(3) Comparing the desulphurization effect of the two methods, a higher efficiency can be attained with negative DC corona discharge combining water absord method, but it only fit to dispose small flux flue gas.