Application Fundamental Research On Flue Gas Dry High-efficiency Desulfurization And Denitrification In Coal-fired Power Plants

Ultra-low emission is beening applied in China,but the haze weather has not been effectively alleviate.As the main flue gas desulfurization technology,wet desulfurization technology will discharge a large amount of water vapor into the atmosphere.This paper analyes the the concept of soluble salts and condensable particles matter,and the limitations of the existed concept of condensable particles matter and detection methods,which will underestimate the emission of the actual soluble salts.The treatment mode of FGD gas is analyzed.It is concluded that the ultra-low emission technology can not effectively remove soluble salts.It is considered that the composition of FGD wastewater and water vapor in the FGD are similar to tha,and it is calculated that about 56 million tons of soluble salts are discharged to the atmosphere each year,which is the main cause of haze.The dry and high-efficient removal technology for coal combustion polutants is put forward.The pilot experiments of desulfurization and denitrification are carried out on 170 t/h pulverized coal furnace and 75 t/h CFB boiler and 220 t/h pulverized coal boiler.The technical and economic results show that the desulfurization and denitrification effect of the technology can reach ultra low emission,and the sulfur content of fly ash is up to the standard,and the economy is economical.The technology without water consumption will not cause soluble salt emissions.The reaction between HNCO and SO2 was carried out in the existence of N2,N2+O2 and N2+H2O.The reaction products was verified by elemental analysis and TGA analysis.The solubility of the products was analyzed by different polar solvents.The structure of the three products was conjectured by the analysis of the FT-IR and LC-MS results.It can be showed that HNCO can be reacted with SO2 in all three atmospheres.The products are solid at normal ambient temperature and can be dissolved in the strong polar solution DMSO,DMF,DMAc and pyridine.the structure of three products is conjectured in the end.The high temperature heating corrosion test was carried out on the Q245R bare steel samples and inorganic ceramic coating modified samples at 550? and 30%HNCO gas.The corrosion degree was compared by weight gain method.The microstructure of the specimens after different corrosion time was observed by metallographic microscope,and the electrochemical tests results were compared.The results show that the corrosion of the bare steel is more serious and the corrosion of the coated is lighter,the pitting corrosion of the bare steel surface is more severe,too.The coating has a slight crack but the whole surface of basement is still covered completely,and the contact between the steel and the corrosive gas is hindered.The the inorganic ceramic coating modified steel has better corrosion resistance.Therefore,conventional inorganic ceramic coating can be used for anticorrosive treatment of boilers,and is suitable for the power plants that use dry and highly-efficient technology.