Study On Desulfurization Ultra-low Emissions Renovation Of 660MW Supercritical Unit In Weijiamao Power Plant

Restricted by the energy structure of lack of gas and oil in China,coal accounts for about 70%of the primary energy structure in China,and the SO₂ emission of China has a certain positive correlation with coal consumption.In China,coal-fired power plants consume more than half of the total coal consumption in China,so coal-fired power plants are the major emitters of SO₂.In order to further reduce the SO₂ emissions from coal-fired power plants,the relevant departments of the state issued the"action plan for energy saving coal upgrading and transformation（2014-2020）",the action plan requirement of sulfur dioxide emissions standards for35mg/Nm³.Weijiamao power plant in the limestone-gypsum wet flue gas desulfurization technology,desulfurization emissions of SO₂ at about 130mg/m³,does not meet the emission requirements,in order to implement the"action plan"in emissions standards need to desulfurization system of original ultra low emission transformation.Weijiamao power plant original desulfurization system is mainly composed of a layer of swirl with a layer of spray system,and can achieve more than 95%desulfurization efficiency.In order to reduce the ultra low emission quantity,save investment,the ultra low emission project is renovating the original system into a cyclone with three layer spray,and reserving an additional layer of spray.Liquid gas ratio of the desulfurization system transforms from 9 to 19.2,the residence time of flue gas is increased from 6s to 9.5s,the number of each nozzle spraying layer increases from 92to 150.The desulfurization efficiency can reach more than 99%,the concentration of SO₂ emission is below 23mg/m³.These all meet the emission requirementsFor the new project investment and operation cost of power plant desulfurization Weijiamao ultra low emission transformation and new environmental benefits and other aspects of the economic analysis:total investment in the desulfurization of ultra low emission transformation unit investment is 19.45 million yuan,14.73 yuan/kW,the new annual operating cost of 6.6038 million yuan,according to the generating unit annually operating 5500 hours,ultra low emissions electricity price increases 0.005yuan/kWh after connecting Internet.The new electricity sales revenue is 36.3 million yuan.According to the analysis of net income sensitivity after the power plants renovating into ultra low emission plants,the main factors affecting the net income of desulfurization system are generating hours and compensation price,but price fluctuation of coal sulfur and limestone changes have little effect on net income.The same in other factors,with the increase of hours generating net income will continue to increase,not considering the engineering investment under the condition of power plant.There is basically no loss.But if the project investment is counted,there exists loss when the power generation operates 3000 hours.When other conditions remain unchanged,with the decrease in price compensation,the new power plant net income decreased.Without considering the project investment,the power plant basically does not have the risk of loss.Considering the investment in the project,when the compensation price is the highest 0.005 yuan,and the annual power generation hours are less than 3,000 hours,the power plant will lose money.