Structure Design Of Polysilicon Directional Purification Furnace Body

In recent years, the development of the solar photovoltaic electricity generation goes fast, which promotes the rapid growth of development of the associated upstream and downstream industries. Compared with other materials in producing solar cell, polycrystalline silicon has a lot of advantages such as higher productivity, lower energy consumption per unit of production and lower cost. It’s used as the main raw material for the production of solar cells. As the most basic part of the photovoltaic industry, the increasing in production of solar cells contributes to the increasing demand for solar grade polysilicon, which makes the technology for polysilicon purification and preparation become one of the hottest research point in the world. As the special equipment for purifying solar grade polysilicon, directional solidification furnace for polysilicon uses advanced computer-control technology to achieve stable directional solidification, and it can prepare large size of the polycrystalline silicon ingot with high quality. It’s efficient, stable, energy-saving and reliable.In this paper, the subject of the study is the structure design and finite element analysis of the furnace body in DPS650equipment which is the directional purification for polysolicon equipment of650kg for short. The furnace body belongs to the vacuum pressure vessel field and the design standard complies with the pressure vessel design standard. We design the whole body based on design by rule, and in local element we use the method of design by analysis to calculate and check the body. In this paper, we shall first briefly introduce the structure of the furnace body which is divided into3main parts including the furnace roof, the middle furnace stack and the furnace stack below. According to process requirements, we placed the nozzle flange, the lifting lug, the handles, the bearings and other accessories for the desired function according to process requirements. Secondly, we did the strength design including the stability of the inner and outer head of the furnace roof, the inner and outer cylindrical of the middle furnace body and the connection flange stress analysis of the furnace body and flange bolts tightening torque analysis and calculation. We do all these work to make sure the optimum sealing effect and the entire body strength meet the design requirements. Thirdly, by using finite element analysis software ANSYS, we established the model of the structure of3parts of the furnace body, and by meshing, defining loads and solving calculating, we analyzed the Vons Mises stress distribution to identify the maximum stress range and the danger point. Through the analysis above we got further check of the strength of the furnace body and ensured that the strength of the design is reasonable. After the analysis, calculation and verification, the stress of the furnace body is far less than the allowable stress, meeting the strength requirements. Meanwhile, we did some empirical analysis on the manufacturing of the directional solidification furnace. We did some research on the manufacturing difficulties of the furnace body. We also did the pressure test to check the quality of the body, which can also ensure the security of the body under the working condition. This paper brings forward the suggestion and ideas to optimize design of furnace body to increases the efficiency of design and to make the directional purification equipment more secure and reliable. We did these analyses to ensure that the furnace can meet the process requirements, and provide a basis protection for the production of polysilicon ingots.