Analysis And Research On The 36 Pairs And48 Pairs Polysilicon Reduction Furnace

With the rapid development of information technology and solar energy industry,the global demand for polycrystalline silicon is increasing rapidly,and the production technology of polycrystalline silicon is developing rapidly too.Process equipment is constantly developed toward large-scalization and energy conservation.The Main polysilicon production technology is improved SIEMENS reduction furnace method.The rods in polysilicon reduction furnace has gradually increased from 12 pairs to 2430,36 and 48 since year2003.As the bigger furnace and improved process,the annual output of one furnace is increased by nearly 15 times.While the power consumption is reduced to 1/5 at the basis of 12 pairs of rods.Therefore the reduction process of polysilicon is a rapid development process.Currently 36 pairs and 48 pairs polysilicon reduction furnace can generate the maximum production rate at the lowest energy consumption of reduction in China.But the technology is very new,only few of manufacturer is using.Operating parameter and process curve are various as different manufacturer.The production rate and cost are vary widely.There is no uniform conclusion about whether the output of large reduction furnace can be improved or not.There are many problems in operation process such as,switching furnace,growth is not stable,the capacity does not reach the design goals etc.This paper works on looking for solutions of these problems in operation process of improved SIMENS furnace especially for 36 and 48 pairs of rods.The scheme is:Utilize STR and ANSYS software to simulate the air flow in the polysilicon reduction furnace and integrate chemical vapor deposition principle to determine causes.Then establish process adjustment concept and optimize operation program.At last verify and adjust while production.The operation program can be optimized by verifying the supply curve,current curve,nozzle,equipment structure,silicon core etc..Therefore the above problem in large multi-pair rods furnace will be solved accordingly.This gives direction for process parameter optimization also.Operation program and production parameter from repetitive test has a certain generality.It can be used to compare the same type of reduction furnace and verify parameter base on supply cure and current curve.Therefore we can reach the goal of shorten test cycle of large furnace and increasing capacity basis of lower cost.