| The technology of low temperature plasma from pulse corona discharge came into being at the end of 1970s, which is one efficient method of fuel desulphurization and denitrification. Since then, researchers of many countries have been working on it for making it perfect.In this paper, it is reported that the experiments have been made on both sectional and integrated equipment for dust collection and desulphurization denitrification, such as, desulphurization and dedust test by discharge plasma, design of the device with original rotating net plate and test of collecting dust and desulphurization denitrification, thermodynamic analysis on nitric oxide removal by low carbon hydrocarbons and corona discharge; synergistic treatment of SO2 and NO in fuel by pulse corona discharge and catalyst; thermodynamic functions calculation of metal oxides reacting with SO2 and the desulphurization reaction model. The main achievements and results are as follows: Through the test result of corona discharge desulphurization, It is shown that desulphurization efficiency of positive pulse corona discharge is higher than negative DC corona discharge's, desulphurization efficiency of ammonia and steam coming in reactor from discharge polar is higher than that from fuel entrance.Tests are carried out , which are collection dust, desulphurization and denitration by using electrical precipitator with the original rotating net plate, result is shown that the lower collecting dust efficiency is, the higher wind speed of fuel pipe is. When wind speed is 2.1m/s, the bigger rotation speed is, the bigger collecting dust efficiency of dry method is, as rotation speed is 12 rpm, collecting dust efficiency is 99%. When rotation speed is 6 rpm and aerating water, collecting dust efficiency is more than 99%. Under the condition of aerating water or ammonia, rotation plate does not influence desulphurization and denitration efficiency. However, on the condition of making dust into reactor, desulphurization efficiency of rotation plate is higher than 5% in comparison with fixed plate. The corrosion of Cu-Cr-Al-Ni alloy discharge pole occurs first in the interface between Cu and Cr in 3.5%NaCl+4.5mol/L NH3 solution, and the Cr phase of Cu-Cr-Al-Ni alloy is more easy to flake off with the weight amount of load increasing. The morphology character of corrosive wear of Cu-Cr-Al-Ni alloy in 3.5%NaCl+4.5mol/L NH3 solution is mainly in form of cutting, and with corrosion, and the synergistic effect between corrosion and abrasion results in the increase of corrosive wear mass loss of alloy.The result from the test on NO removal by pulse corona discharge with low carbon hydrocarbons is identical with that from the thermodynamic analysis of nitric oxide removal by low carbon hydrocarbons. As 298K,ΔGθof reactions, which are the reaction of methane, ethane, ethylene, ethine, propane and propene with NO, it is indicated that positive reaction tendency of ethane, ethine, propane and propene is very strong, and that of propene is the strongest.The experiments show that SO2 and NO in the smoke can be removed efficientlyby pulse corona discharge together with CuO/γ- Al2O3.When pPulse voltage is 40kV, inlet fuel temperature is 80℃,outlet fuel temperature is 40℃,fuel flow velocity is 1.3m/s,initial concentration of SO2 is 1400mg/m3, and initial concentration of NO is 350 mg/m3, SO2 removal efficiency is above 85%, and NO removal efficiency is 30%. The surface structure of the catalyst has been investigated by IR and XRD, it is found that catalyst has better activity at low temperature by synergistic action with pulse corona discharge.By calculatingΔG, Kp of desulferization agents (CuO,CaO,Fe2O3,MgO ,CeO2) for desulferization reactions and partial pressure of SO2 at equilibrium state by the theory of chemical thermodynamics.The results are indicated that the positive tendency of desulferization reactions are evidencely at room temperature. From the partial pressure of SO2 at equilibrium state and optimum temperature, it is shown that the sequence of the SO2 removal activity is CeO2> CuO >MgO >CaO>Fe2O3. It is the same as the results of calculation by the method of thermodynamics. The reaction of desulphurization is non-catalysis, and its mechanism can be described by the concept of the shrinking core model and the grain model.
|
PDF Full Text Request