Emission And Conversion Of Sulfur In Coal Under Low No_x Combustion Conditions

More and more coal fired power plants begin to use low NOX technology to reduce the emission of nitrogen oxide with the policy to reduce nitrogen emission getting more perfect and strict.Air-staged combusting has become the preferred low NOX combustion technology of most coal-fired power plants because of its advantages like economy, effectiveness, simplicity of operator and so on.However, the core principle of air-staged combustion technology is the formation of a reduction oxygen-poor area,which will cause generating of a large number of hydrogen sulfide gas.The hydrogen sulfide gas is the main cause of high temperature corrosion of boiler water wall.Most of the current research about sulfur release and conversion during coal pyrolysis are completed at a slow heating rate and a big particle size.This study was completed at a heating rate about 1000℃/s by drop tube furnace.The char samples after pyrolysis were analyzed by thermo gravimetric analyzer and sulfur determination instrument.A predictive kinetic model of the release of sulfur compounds from coal at the high heating rate was also presented.The results show that the release amount of sulfur increases with the increase of temperature.Pyrite sulfur release faster than the organic sulfur and its release temperature is lower.And the pyrite in coal has decomposed completely before 900℃.Most of the sulfur of char samples after pyrolysis exist in the form of organic sulfur.For most of the coal samples, sulfur content of char samples account for about 50% of sulfur content of original coal samples. The validity of the predictive kinetic model was verified by the comparison with experimental results.