Experimental Study Of Desulfurization In Flue Gas With Corona Induced Plasma

The pollution of our country caused by SO₂ is very serious now. Cutting down the emission of SO₂ is the emphasis at environmental protection in the future. Desulfurization technology consists of remove sulfur from fuel, sulfur capture in the combustion process and fuel gas desulfurization. Fuel gas desulfurization includes dry, semi-dry and wet systems. The wet limestone-gypsum desulfurization is a riper technology, used in many pants.Traditional fuel gas pollutant treatment technology has some shortcomings, such as poor efficiency or high investment. It can not fit for the national conditions of our country. Removal of SO₂ by plasma is a kind of new-type desulphurization craft and removal of SO₂ by corona is a better craft used in plants. The domestic and international scientists have all carried on a lot of meaningful research to plasma desulphurization technology, made some achievements tentatively. Their research consists of discharge theory, discharge characteristic, reacting mechanism, power and reactor structure. But many work had to be done to make this craft running in a good state.A needle-plate corona reactor is established in this project, use of high-voltage direct current corona discharge produce low-temperature plasma. We study simulated SO₂ gas, researching and concluding the general rules of the low-temperature plasma degradation of SO₂.Firstly we research the power discharge phenomena and the nature of plasma. The results showed that: the discharge inception voltage and breakdown voltage of negative corona is higher than positive corona. O₃ concentrations increase as the voltage increases and gas flow rate decreases. O₃ concentrations in positive corona are higher than negative corona. However, the negative corona can be run at a higher voltage, so it is produce more oxygen plasma and O₃.We study the different discharge parameters on the desulfurization efficiency in this experiment. The results are as follows:1.In the same conditions, the desulfurization efficiency of negative corona is higher than positive corona.2.The desulfurization efficiency increases with the voltage increases, the highest efficiency is 80.2%,when the conditions are negative corona, polar distance is 1cm, voltage is 1kV.3.To a certain power extent, with the increase of power supply, the deSO₂ efficiency will increase. When electric power less than 2 W, desulfurization efficiency increase faster; electric power more than 6 W, the desulfurization rate of increase has not obvious.4.The desulfurization efficiency increases with the gas flow rate reduces. In the negative corona, when gas flow rate are 100L/h,150L/h,200L/h, the desulfurization efficiency are 80.2%, 73.9%,67.3%.5.The desulfurization efficiency reduces with SO₂ initial concentration increases. Under the 15 kV voltage, when the SO₂ initial concentration is 1338 ppm, the highest desulfurization efficiency is 80.2%, while the SO₂ initial concentration is 2383 ppm , the highest desulfurization efficiency is just 67.9%.6.Amount of NH3 is proportional to desulfurization efficiency. When the ratio of ammonia to SO₂ is below 2, SO₂ removal rate is low, as the mount of NH₃ increase, SO₂ removal rate increase rapidly. When the ratio of ammonia to SO₂ is greater than 3, growth of SO₂ removal rate has stabilized, up 83.8%.7.With the ratio of ammonia to SO₂ increasing, the concentration of NH₃ in the exhaust gas is also increasing.8.Change the inlet position of ammonia can not enhance desulfurization efficiency, but it can change the resultant composition.Finally, we conclude the problems encountered in the experimental process, and propose solutions...