Separation of air by cryogenic distillation and installation using thermally interconnected medium and low pressure columns

摘要

A quantity of purified and compressed air is cooled in an exchanger to a cryyogenic temperature and conveyed to the medium pressure column, and flows enriched in oxygen and nitrogen(LR, LP) are sent from the medium pressure column to the low pressure column ; flows of nitrogen- and oxygen-enriched fluids are withdrawn from the low pressure column and passed to the exchanger.The ratio of the total quantity of air admitted to the total vol of the exchanger is greater then 3000 Nm3/h.m3, more preferably 3000-10000 Nm3/h/m3, and the ratio of oxygen leaving the exchanger to the total section reserved for oxygen flow, is less than 25Nm3/h/cm2. A quantity of purified and compressed air is cooled in an exchanger to a cryogenic temperature and conveyed to the medium pressure column, and flows enriched in oxygen and nitrogen (LR, LP) are sent from the medium pressure column to the low pressure column; flows of nitrogen- and oxygen-enriched fluids are withdrawn from the low pressure column and passed to the exchanger. The ratio of the total quantity of air admitted to the total volume of the exchanger is greater then 3000 Nm3/h.m3, more preferably 3000-10000 Nm3/h/m3, and the ratio of oxygen leaving the exchanger to the total section reserved for oxygen flow, is less than 25Nm3/h/cm2. An independent claim is also included for the installation which effects the process.