Experimental And Mathematical Model Study Of A New Spray Scattering Tower For Flue Gas Desulfurization

Under the background of super-clean emission,the relevant departments of the state have put forward stricter requirements on the emission of flue gas pollutants from coal-fired power plants.In the aspect of SO₂ removal,the traditional desulfurization equipment can not meet the requirements of economy and environmental protection at the same time only through modification,so it is urgent to develop and research new desulfurization technologies and facilities with higher efficiency and economy.the spray scattering deep desulfurization technology was put forward by combining the more matural traditional spray technology with bubbling technology.This technology not only overcomes the main shortcomings of the traditional spray tower and bubble tower in improving the desulfurization efficiency,but also retains the respective technical advantages of spray tower and bubble tower.It is a new desulfurization technology with advanced technology and feasible economy,and has good research prospects.The experimental platform of spray scattering tower was built and the influence of key operating parameters such as liquid-gas ratio,immersion depth of scattering tube,slurry pH and mass concentration of CaCO₃ on desulfurization efficiency of spray scattering tower was investigated by using control variable method.The energy consumption of spray scattering tower was simply analyzed combined with the spray scattering tower retrofitted by 300 MW unit of a power plant.The results show that the desulfurization efficiency of the new spray scattering method is much higher than that of the traditional spray or bubbling method under the same working conditions;with the increase of liquid-gas ratio,the depth of immersion in the scattering tube,the slurry pH and the mass concentration of CaCO₃,the desulfurization efficiency increases gradually;the SO₂ concentration shows a stronger adaptability than the traditional desulfurization method.Considering the operation cost only,the energy consumption of the main equipment of the spray scattering tower is about 1/2 of that of the spray tower.Based on response surface methodology,the relationship between several key operating parameters and desulfurization efficiency of the new spray scattering tower was explored.The performance prediction model of the desulfurization tower was obtained by regression analysis.By the model analysis,not only the influence of various factors on the desulfurization efficiency of the spray scattering tower but also the influence of the interaction of the two factors on the desulfurization efficiency was investigated.The results show that the depth of immersion in the scattering tube has the greatest influence on the desulfurization efficiency of the spray scattering tower,followed by the liquid-gas ratio,while the concentration of SO₂ and CaCO₃ have relatively small influence on the desulfurization efficiency.At the same time,the interaction of liquid-gas ratio with the depth of the scattering tube and the interaction of the depth of the scattering tube with the mass concentration of CaCO₃ have a great influence on the desulfurization efficiency of the spray scattering tower.A three-dimensional mathematical model coupling the gas-liquid flow and desulfurization reaction process in spray scattering tower was established.Based on the double-film theory,a simplified mass transfer model of SO₂ between the gas phase and the liquid phase in spray scattering tower was established,and the mass transfer model was used as the source term of interphase interaction coupling with the three-dimensional gas-liquid flow model through Fluent self-defined function.Under a basic working condition,when the removal reaction was stable the simulation results of each measuring point in the flue gas flow were compared with the experimental values.It is found that the deviation of the desulfurization efficiency is 2.12%,and the mathematical model is basically accurate and reasonable.The model was used to simulate the spray scattering tower experiment platform.the simulation results are basically consistent with the experimental results.In this paper,the experimental and mathematical model of the new spray scattering tower were studied,and the desulfurization characteristics of the spray scattering tower were comprehensively understood,and the mechanism of its efficient SO₂ removal was revealed,which will provide a theoretical basis for the further design,optimization and promotion of the spray scattering tower.