Dissertation > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Exhaust gas processing and utilization > Desulfurization and desulfurization

The process of analysis and research of limestone wet flue gas desulfurization tower

Author HouQingWei
Tutor LuChunMei
School Shandong University
Course Thermal Power Engineering
Keywords desulfurization numerical simulation k-ε model velocity field temperature field
CLC X701.3
Type Master's thesis
Year 2005
Downloads 455
Quotes 10
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Limestone Wet flue gas desulfurization(WFGD) technology with high efficiency is being applied most widely for control technology of SO2 all over the word. In the whole FGD system, desulfurization process mainly takes place in the absorber as the hard core and the complicated flow and temperature field influencing the desulfurization efficiency is used the key factors. But the situation in the absorber is hardly revealed only through experiments, and numerical simulation will be taken as the important part for understanding the progress in the absorber.In the paper, the typical absorber of WFGD has been researched as the object on Finite Element Method(FEM) and continuous theory based on the absorber((?)13×38m) of that 300MW turbin. The k-ε model and SIMPLE method are introduced with stagger nets and variable of velocity and press when 3D velocity and temperature field are calculated through fluent6.0 with nets constructed by Gambit in the absorber. In addition, the distribution of SO2 concentration also has been forecasted by the assimilation of heat and mass transfer. Based on the simulation results, the distribution of flow and temperature have been analyzed in detail.Through the results, pH value should been kept from 4.8 to 5.5 with SO2 deffuseness which was the mainly control steps during the operate of WFGD. In order to enhance the mass transfer of gas and liquid and improve the desulfurization efficiency, the spry levels should be located the over-flow area of flue gas from 10m to 15m above the sump surface; The column absorber constructed can been invested less than types, the important thing is that the arc face can make the ingoing gas circumgyrate and ascend and enhance the turbulence of the flue gas current; The turbulence situation can been enhanced and the time of gas-liquid contact relatively shorten when the low levels being activated; but when the high levels being activated, the time of gas-liquid contact relatively been postponed and the turbulence situation been impaired. Therefore, the low and high levels should spray at the same time for the sake of enhancing the turbulence intension and extending the time of gas-liquid contact, which mostly improves the desulfurization efficiency; The distributionof SO2 concentration in the absorber can be forecasted on the assimilate principle of heat and mass exchange. And the means that predigests the mass transfer is feasible to analyze qualitatively although the method has more difference compared with practical desulferization.The desulfurization efficiencywhen drawed by numerical simulation was consist 72% of the practice when the low and high levels oprated which the main element was that the assimilate principle had been introduced without the progress of mass transfer; Vaporing slurry could make the velocity grades of outlet gas along the height enlarge and occur the liquid sediment then increase the erodibility of the lower face in the flue channel. Accordingly, the flat outlet should been employed and the embalmment also been strengthened in the system operation.The conclusion in this thesis has basic coherence with the practical operation, which shows the thing that the model applied during the simulation process is compatible and it is possible that forecasting flow and heat transfer, so the simulation method is very helpful for the design and optimization during the practice of WFGD.

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