Improvement Of Dust Removal Performance Of Spray Absorber And Its Application In Yangliuqing Project

Wet limestone-gypsum desulfurization technology is currently the most widely used flue gas desulfurization technology.The core equipment is spray tower which has certain dust removal capability.How to increase its dust removal efficiency,such that it can be used an auxialliary dust removal equipment to meet the latest ultra-low dust emission requirements is of significant economical importance.In this paper,the dust removal efficiency and influencing factors of the spray tower are deeply analyzed.It is found that the dust removal efficiency of the spray tower is determined by the tray installation,flue gas flow rate,nozzle droplet atomization particle size,spray layer distance,number of spray layers,the concentration of particulate matter of flue gas,etc.By taking such measures as installation of the tray,increasing flue gas flow rate,reducing droplet size of water atomization,increasing the spray layer distance,the dust removal efficiency can be remarkably increased,from68%of a traditional spray tower to 96%.In addition,The internal flow field of the improved spray tower optimization was done by CFD numerical simulation.The results showed that the deviation of the flue gas velocity distribution into the absorption tower is reduced from 50%to 25.3%by the installation of the tray,with great improvement of the flue gas velocity distribution.Upon on the ultra-low dust emission requirements for the Units#7 and#8 of the Yangliuqing Power Plant,by comparing with the retrofit scheme with installation of wet-ESP,the one to use the improved spray tower was selected.Through the analyses of the feasibility of engineering implementation,techno-economy,the scope of application and optimization potential,it is found that the improved spray tower has the advantages of low difficulty in retrofiting,short construction period,low operating cost and low investment cost.Compared with wet-ESP schemes,for the retrofit with the improved spray tower,the construction period can be shortened 55 days;the investment costs can be reduced by 14.84 million yuan?single unit?,and the operating costs can be reduced2.09 million yuan?single unit?.The improved spray tower was used in Unit#8 of Yangliuqing Power Plant.After some operation time,measurements of the dust removal performance were conducted.The data showed that when the inlet dust concentration was 16.8 mg/m³,deducted from the impact of particulate matter entrained in the flue gas,the dust removal efficiency reached 85.7%,the dust emission at the outlet was 3.36 mg/m³,less than 5 mg/m³ of the design requirements.Compared with other solutions to the low dust emissions,the use of the improved spray tower technology can not only ensure low SO₂ and dust emissions,but also reduce the retrofit difficulty,retrofit period and investment costs.It is a rather promising intergrated technology with simulantenous removal of SO₂ and dust.