Method for the integration of a nitrogen liquefier and liquefaction of natural gas for the production of liquefied natural gas and liquid nitrogen

Abstract

A method for the integration of a nitrogen liquefier and liquefaction of natural gas for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a nitrogen liquefaction unit and providing a natural gas liquefaction unit. Liquefaction of the nitrogen can be achieved via a nitrogen refrigeration cycle within the nitrogen liquefaction unit. Liquefaction of the natural gas can be achieved through the use of natural gas letdown and a second nitrogen refrigeration cycle. The two liquefaction units can be integrated via a common nitrogen recycle compressor, thereby providing significant capital savings.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Application Ser. No. 62 / 201,947, filed on Aug. 6, 2015, U.S. Provisional Patent Application No. 62 / 305,381, filed on Mar. 8, 2016, and U.S. Provisional Application Ser. No. 62 / 370,953 filed on Aug. 4, 2016, all of which are hereby incorporated by reference in their entireties.TECHNICAL FIELD OF THE INVENTION[0002]The present invention generally relates to a method for efficiently producing liquefied natural gas (LNG).BACKGROUND OF THE INVENTION[0003]Many locations utilize a high pressure (transmission) network and a lower pressure (distribution) network to supply natural gas through a local area. The transmission network typically acts as a freeway to economically send the gas over long distances to the general area, while the distribution network acts as the roads to send the gas to the individual users within a local area. Pressures of these networks vary by location, but typical values are between 30-8...

AI Technical Summary

Benefits of technology

[0009]The present invention is directed to a method and apparatus that satisfies at least one of these needs. In certain embodiments, the invention can provide a lower cost, more efficient and flexible method to produce LNG. For example, in certain embodiments, the invention can also include coproduction of liquid nitrogen (“LIN”). In additional embodiments, the invention may include varying the production rates of either or both the LIN and LNG, based on power costs, product demand, and / or supply levels.

Problems solved by technology

As such, in these locations, potential refrigeration capacity is wasted.

Additionally, there are instances in which producers of the nitrogen gas feeding the pipeline do not operate at 100% of equipment design capacity, and therefore, large nitrogen compressors are either not operating or not operating at optimum capacity.

As such, the nitrogen producing equipment may be designed to be underutilized during many operating scenarios when other systems are not able to accommodate increased loads.

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