AIR SEPARATION METHOD AND APPARATUS

摘要

A method and apparatus to produce oxygen and nitrogen co-products in which a compressed a compressed and purified air stream is cooled, fully or partially condensed and then rectified in a main distillation column to form a nitrogen-rich vapor column overhead and crude liquid oxygen. A crude liquid oxygen stream is depressurized and then stripped in an auxiliary distillation column with a stripping gas to produce an oxygen-rich liquid. The nitrogen-rich vapor column overhead from the main distillation column is used to form a nitrogen product and the crude liquid oxygen is partially vaporized to produce the stripping gas, a residual oxygen- rich liquid and liquid nitrogen reflux to the main distillation column. The oxygen product is formed from the residual oxygen-rich liquid by either providing the heat exchange duty in condensing the compressed and purified air stream or by condensing nitrogen-rich vapor used in refluxing the main distillation column.