| The absorber is the main structure of the desulphurization technology system in coal-fired thermal power plant. The absorber structure is general a thin-wall tower structure. A variety of ducts and support beams are installed inside the tower, the holes of ducts and smoke import and export are set on the tower body, and rolled shapes are installed to strengthen the structure. The entire structure is complex.The flue gas desulphurization device connects the boiler and chimney, its construction and running quality not only relate to how to fully bring into play the environmental protection benefit of the flue gas desulphurization of the thermal power plant, but also have a great significance on the boiler's stabilization and safe operation of the thermal power plant. The seismic response analysis of the flue gas desulphurization absorber structure is an important safeguard on the safety and stability of the flue gas desulphurization device. Meanwhile, it has a very important influence on the safety and economy of the whole thermal power plant, even the whole electric network.Based on the documentations which have been existed, researches on the absorber structure are extremely rare at home and abroad. So the seismic response analysis on the flue gas desulphurization absorber structure is even less. In this paper, by utilizing the finite element method, the model building analysis and seismic response analysis of flue gas desulphurization absorber with high tower are carried out. And the seismic response laws of the absorber structure are obtained. The thesis accomplished the main subjects as follows.1. Firstly, the finite element model conforming to the actual project is established in this paper. There is some slurry in the absorber. It can be divided into two cases whether considering the slurry or not when establishing the model. When the slurry is considered, because of the slurry's effect on the structure is very complex, this paper uses three methods respectively to consider the effect which the slurry affects on the structural seismic response: additional mass method, Housner spring-mass model and the direct dynamic coupling method.2. The dynamic properties analysis of the absorber is performed on the four models respectively which are established on the above. The first thirty natural frequencies and basic mode shape of different models of the absorber structure are obtained. By comparing with different models, the reasonable model was obtained, which is used in the next step of calculating the seismic response. By analyzing the relative codes of thin-wall tower structure in domestic, the approximate calculation formula of basic natural vibration period can be drawn as follow.3. By utilizing the acceleration response spectrum analysis, we can find out maximum internal force and the most main design factors of each structural element to provide some references for its structural design. The main conclusions can be drawn: the difference of structural stiffness between two horizontal directions is small. The X direction's seismic resistant properties are more weaken than the other direction. The sideway curves belong to the style of bending. The connections between the smoke import and the absorber body is the weak part of the structure.4. By utilizing finite element method, the time-history analysis is calculated in this paper. Thus, the changing laws of the absorber structural response varying with time can be obtained under strong ground motion. By comparing with the displacement of nodes between two models of the absorber, the differences between two models can affect the partial response, however, the influence on the whole structural response is small. The reactions of the first model are larger than the forth model because of the swashing of the slurry decreasing the actions which the load works on the absorber structure.The conclusions and experiences acquired in this paper provide some advices for seismic analysis of similar large-sized structures. |
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