Use of liquefied natural gas (LNG) coupled with a cold expander to produce liquid nitrogen
US5141543A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1991 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Apr 26, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25J2245/90
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention relates to a process for the liquefaction of a nitrogen stream produced by separating air components, by using the combination of cryogenic distillation with improved refrigeration. Very cold liquefied natural gas (LNG) is employed as refrigerant, with the LNG currently being revaporized for transportation. Multi-stage component compression is used, with the component feed to each compression stage being precooled using sequential refrigeration from the LNG. Expander means for the coldest air component product stream provides supplemental refrigeration at the cold end beyond that which is available from the refrigerant LNG. In a preferred embodiment, the feed nitrogen stream(s) are compressed to at least 300 psi in a multi-stage compressor with interstage cooling provided by heat exchange against vaporizing LNG; the resulting compressed stream is directed into first and second nitrogen substreams, followed by further cooling of the first substream by heat exchange against vaporizing LNG and then expanding the cooled first substream to produce an expanded nitrogen substream. Condensing of the second compressed substream against both vaporizing LNG and the expan…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.