20130042646 | Production of High-Pressure Gaseous Nitrogen - An improved process for producing elevated pressure nitrogen including providing an air separation unit with at least two columns, an LP column and an MP column. Also including extracting a nitrogen stream from the MP column and extracting a rich liquid from the bottom of the MP column, and providing at least a portion of the rich liquid stream to a first vaporizer. Also including introducing a portion of the nitrogen stream into the first vaporizer, thereby producing a boil-off gas, and warming at least a portion of the nitrogen stream in a heat exchanger, thereby producing a product nitrogen stream. Also including warming at least a portion of the boil-off gas in the heat exchanger, thereby producing warm intermediate stream, expanding the warm intermediate stream in an expander, thereby producing a quantity of work, and a low pressure intermediate stream, and introducing the low pressure intermediate stream into the LP column. | 02-21-2013 |