Method And Apparatus for High Purity Liquefied Natural Gas

Abstract

A novel method and system for liquefying and distilling natural gas into high purity liquid methane (LNG) and NGL product streams. Heat exchangers and distillation towers are configured to produce high purity liquefied natural gas (LNG) and NGL product streams, while also rejecting excess nitrogen contained in the inlet gas stream, utilizing liquid nitrogen as the process refrigerant. A molecular sieve pretreatment system is configured to utilize the vaporized nitrogen stream for regeneration of the molecular sieve beds which are designed for removing water and carbon dioxide from the inlet gas stream

Description

CROSS-REFERENCE[0001]This application is a continuation in part to U.S. patent application Ser. No. 12 / 765,750, filed on Apr. 22, 2010, priority of which is claimed herein and the entirety of which is hereby incorporated by reference.DESCRIPTION OF RELATED ART[0002]The present application relates to liquefaction of natural gas, more particularly, to a more environmentally friendly method and system for providing high purity Liquefied Natural Gas (LNG) with reduced cost by utilizing liquid nitrogen (LIN) as the LNG condensing medium and process refrigerant.[0003]Note that the points discussed below may reflect the hindsight gained from the disclosed inventions, and are not necessarily admitted to be prior art.[0004]The advent of high cost in transportation fuels such as gasoline and diesel (based on high petroleum costs) and the coincident very low cost in natural gas has prompted the transportation industry to switch fuels to compressed and liquefied natural gas. Besides the lower c...

AI Technical Summary

Benefits of technology

The system uses liquid nitrogen refrigerant to help liquefy and separate natural gas into its components, such as ethane. The system achieves a high recovery rate of ethane and other contaminants, while reducing energy input and emissions. Overall, the system achieves a high level of efficiency in gas processing.

Problems solved by technology

However, the liquefaction of natural gas into a Liquefied Natural Gas (LNG) product is currently performed using large and capital expenditure intensive equipment.

More importantly, the LNG from a typical liquefier will generally only meet an industrial or commercial grade standard sufficient for gas utility of a power plant use, not sufficient high quality enough for vehicle use.

The cost of trucking LNG fuel from a large distant LNG facility is prohibitive.

Images