Medium-purity oxygen prodn. - uses part of nitrogen current to counter cooling losses and heats remainder

摘要

The method produces medium-purity oxygen by low-temp. rectification of air, the latter being compressed, cooled and fed to a decomposition unit, where oxygen and nitrogen are extracted. To counter cooling losses, a current of gas from this unit is used to perform work as it is expanded. A first part of the current of nitrogen is expanded to counter these losses, performing work in the process, while the remainder is heated to ambient temp. and then also performs work as it is expanded. Heating can be by heat exchange with the air to be decomposed.