The Structure Finite Element Analysis Of Desulfurization Tower With Double Large Exhaust Openings

The desulfurization tower is the core equipment of flue gas desulfurization, mainly composed of tube body, smoke box, bracket, bearing ring beam and other components, mostly is large and thin shell structure. For the need of techniques and design, various kinds of pipeline and supporting beam are set in the desulfurization tower, which have high porosity, these measures make the desulfurization tower be a complex structure. For this kind of structure, there is no completely applicable specification available, and the structure design depends on departed engineering experience to a large degree. So it is lack of corresponding theoretical analysis and guidance, and it is necessary to do in-depth research for this kind of structure.The desulfurization tower of Inner Mongolia China Coal MengDa New Energy Chemical Company is utilized as the practical engineering background for this project. According to the characteristics of the structure, the paper uses finite element analysis software MIDAS/Gen to simulate and analyze the structure in finite element analysis. The models of desulfurization tower structure and its important parts(bearing ring beam and venturi top beam) are established, and the static calculation under corresponding conditions of the model is completed, to analyze the extreme value and the distribution of structural response. Then, the results of local analysis and the integral analysis are compared under various operating conditions, aware of the impact of structural mechanics characteristics from different modeling method. Besides, the separate analysis model of exhaust smoke box and common analysis model of stent and exhaust smoke box are established respectively to study combined action of stent and smoke box. And the two models are calculated under the same conditions, results of which are compared to analyze the impact of the synergy of stent and smoke box to mechanical characteristics of smoke box. The main research work and conclusions in this paper is as follows:(1) The integral analysis is carried out on the desulfurization tower, the result of which shows there is serious stress concentration phenomenon at the joint of tube and venturi top beam. As the venturi top beam is under a large load produced by the weight of bottom components and ash hopper dust, and pass it to the bottom edge of tube, forming the equivalent concentrated load, and producing a lot of stress and deformation on the tube. Meanwhile, the distribution of stress and deformation of the ring beam has "eccentric" phenomenon, causing calculation results of the structure have a larger gap in the front and back of the structure. Besides, venturi top beam is restrained only on the outer ring beam, radial beam and the inner ring beam are not set any form of constraint and supporting structure. So there appears large deformation on the annular beam near the midpoint and great stress at the joint of the radial beam and outer ring beam.(2) The local analysis is carried out on important parts(bearing ring beam and venturi top beam) of the desulfurization tower, comparing the results with which of the integral analysis. It shows uneven distribution of stress and deformation of ring beam in the integral analysis, and the results in the side connected to the bracket if larger, while there's no obvious distribution of stress and deformation in local analysis, and the results are seriously different from which in integral analysis. The distribution of stress and deformation of venturi top beam is basically consistent in local analysis and integral analysis, but the great value of stress and displacement is difficult to contrast from the analysis of two models under the influence of gravity. The stress distribution law of enturi top beam is completely different in local analysis and integral analysis under dust load. So, it's visible that local analysis is difficult to accurately response actual mechanical characteristics of important parts of the desulfurization tower, and should not provide reference basis for preliminary design of structure(3) The models used to analyze smoke box only as well as smoke box work together with stent are established to analyze the influence of the combined action of the stent and smoke box to the performance of smoke box, calculated under the same conditions, and the results of two models are compared. It shows that the stress of two models has a great difference between the two models, especially the stress distribution is more homogeneous when considering the common role of stent and smoke box than analyzed separately. There is obvious error of structural internal force when the smoke box is calculated separately, and the corresponding displacement is larger. So the stent in the bottom of the smoke box can not only reduce displacement of the smoke but also have a good coordination function to its deformation. As the stent is helpful to optimize the mechanical characteristics of smoke box, and can significantly enhance its bearing capacity, the combined action of stent and smoke box should not be ignored when analyzing the mechanical properties of smoke box.