This application discloses a steam regulating valve
assembly for a
polycrystalline silicon differential pressure coupled
distillation column. The steam regulating valve
assembly is installed on the steam pipeline to regulate the amount of steam entering the
reboiler. The steam regulating valve
assembly includes: a main regulating valve unit, which is installed on the steam pipeline and has a first through-hole, and is used to regulate the flow rate of the main steam during the stable operation phase of the
distillation column; and an auxiliary regulating valve unit, which is also installed on the steam pipeline and has a second through-hole, which is smaller than the first through-hole, and is used to perform micro-flow control of steam during the start-up phase of the
distillation column.