Reactor for producing polycrystalline silicon, system for producing polycrystalline silicon, and process for producing polycrystalline silicon

摘要

Provided is a technique for obtaining high-purity polycrystalline silicon and for recovering the heat generated by the production of the polycrystalline silicon, the heat being recovered in a highly valuable state. Use is made of a reactor (10) that has an inner wall (11) having a two-layer structure, which is composed of a corrosion-resistant layer (11a) disposed on the inner side that comes into contact with a corrosive process gas, the corrosion-resistant layer (11a) being constituted of a highly corrosion-resistant alloy material, and of a heat transfer layer (11b) disposed on the outer side (outer-wall side), the heat transfer layer (11b) being for efficiently transferring the heat inside the reactor (10) from the inner-wall surface to a cooling-medium channel (13). The cooling-medium channel has pressure resistance that enables hot water having a temperature not lower than the normal boiling point to circulate therethrough. The corrosion-resistant layer (11a) comprises an alloy material having a composition in which the value of R defined by R=[Cr]+[Ni]-1.5[Si] where [Cr], [Ni], and [Si] are the contents in mass% of chromium (Cr), nickel (Ni), and silicon (Si), respectively, is 40% or higher. A reaction for depositing polycrystalline silicon is conducted while regulating the temperature of the inside surface of the inner wall of the reactor to 370ºC or lower.