Study On Industrial Application Of Ultra-Clean Emission Of Boiler Flue Gas Desulfurization Denitrification And Dust Removal

Fossil fuel combustion in fossil fuel power plant produces flue gas,sulfur dioxide and nitrogen oxides in flue gas,which will pollute the atmosphere and lead to acid rain,greenhouse effect and so on.How to reduce the sulfur dioxide,nitrogen oxides and dust emissions,through the desulfurization and denitration dust removal technology to achieve ultra-clean emissions,environmental protection is of great significance.QRC CFB boiler combustion delay coking unit produced high-sulfur petroleum coke,flue gas volume 70×10⁴m³/h.Before the project is reformed,the flue gas desulfurization process technology line is the secondary desulfurization of limestone desulfurization in the furnace and wet cleaning outside the furnace.The technological route of flue gas dust removal is the bag dust removal and wet cleaning,and the flue gas denitrification measures.Before the transformation,SO₂ concentration of boiler flue gas emission was 150mg/Nm³,NO_x concentration was 150mg/Nm³,and smoke dust was 50mg/Nm³.With the continuous improvement of national environmental emission standards,the original flue gas treatment process has been difficult to meet the environmental requirements,the implementation of the environmental protection technology,including denitration unit,dust removal unit and desulfurization unit,in order to achieve the standard discharge of flue gas.Among them,the denitrification unit is a new unit,the dedusting unit and the desulphurization unit are retrofit units,and the denitrification unit sets up two new sets of flue gas denitrification facilities adopting the SNCR process.The dedusting unit relies on the existing two sets of bag filters for efficiency retrofit and the desulphurization unit reforming plan In the existing desulfurization tower desulfurization nozzle and slurry circulation pump.The commissioning showed that the automatic control of denitrification SNCR system urea and dilution water is relatively stable.When the initial NO_x is 150mg/Nm³,the NO_x emission value is controlled below 80mg/Nm³,and the key operational parameters of ammonia slip control are 8mg/Nm³ However,due to the effect of desulphurization of limestone in the furnace,pulsating spikes occur in the emission of NO_x.Boiler dust emissions of 4⁷mg/Nm³,full time less than 10mg/Nm³,less than 5mg/Nm³ requirements.SO₂ emission from the desulfurization tower can reach 35mg/Nm³.Due to the instability of limestone addition and the limited amount of slag discharge,the SO₂ emission is not stable and can not meet the requirement of less than 35mg/Nm³ in the whole period.NO_x average qualified,affected by the instability of limestone addition,the furnace NO_x volatility,can not reach the full time of less than 50mg/m³ requirements.In this paper,the industrialization of flue gas desulphurization denitrification and dust removal of the experimental study,analysis of indicators of data,research changes,accumulation of experience in the adjustment for the super-clean boiler flue gas emissions provide a theoretical and practical case.