Improvements relating to propylene oxide purification

A method of separating impurities from impure PO, the method comprising distilling impure PO in a distillation zone to provide distillate PO of enhanced purity, wherein heat is provided to the distillation zone by a bottoms reboiler and by an intermediate reboiler, the intermediate reboiler providing heat at a lower temperature than the bottoms reboiler. A suitable distillation system is also disclosed. 从不纯的PO分离杂质的方法，所述方法包括在蒸馏区中蒸馏不纯的PO以提供纯度提高的馏出物PO，其中通过底部再沸器和通过中间再沸器将热量提供至蒸馏区，所述中间再沸器以比所述底部再沸器更低的温度提供热量。还公开了合适的蒸馏系统。