SEPARATION METHOD AND APPARATUS

摘要

Separation method and apparatus for separating a gaseous mixture, for example, air, in a cryogenic rectification plant (1) in which a compressed stream (42) is divided into subsidiary streams (126, 128) that are extracted from a main heat exchanger (18) of the plant at higher and lower temperatures. The two streams are then combined and expanded in a turboexpander (36) to generate refrigeration for the plant. The flow rates of the two streams are adjusted to control inlet temperature of a turboexpander supplying plant refrigeration and to minimize potential deviation of the turboexpander exhaust from a saturated vapor state. Control of the expansion ratio can advantageously be applied to allow variable liquid production from the rectification plant.