Methods and apparatus for liquefaction of natural gas and products therefrom

Abstract

A method for cooling natural gas with a refrigerant, one non-limiting embodiment which includes: (A) compressing and cooling the refrigerant to a first pressure to form a compressed refrigerant; (B) splitting the compressed refrigerant into a first stream and a second stream both at the first pressure; (C) cooling the first stream to form a cooled first stream; (D) expanding the cooled first stream to a first expansion pressure to form an expanded first stream; (E) compressing the second stream to a second pressure higher than the first pressure, forming a higher pressure second stream; (F) cooling the higher pressure second stream to form a cooled second stream; (G) expanding the cooled second stream to a second expansion pressure to form an expanded second stream; and, (H) Cooling the natural gas with the expanded first stream and expanded second stream, forming a cooled natural gas stream.

Description

RELATED APPLICATION DATA.[0001]This application claims priority of U.S. Provisional Patent Application No. 61 / 020,699, filed Jan. 14, 2008, and herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to methods and apparatus for processing fluids and products therefrom. In another aspect, the present invention relates to liquefaction of gases and products therefrom. In even another aspect, the present invention relates to methods and apparatus for liquefaction of hydrocarbons and products therefrom. In still another aspect, the present invention relates to methods and apparatus for liquefaction of natural gas and products therefrom.[0004]2. Brief Description of the Related Art[0005]Natural gas may come from a wide variety of sources. For example, the production of oil is many times accompanied by the production of natural gas. Historically, it is not unusual to flare this associated natural gas. More recently, re...

AI Technical Summary

Benefits of technology

[0033]It is an object of the present invention to provide fo

Problems solved by technology

However, in some locations, especially offshore locations, nearby processing infrastructure does not exist, and the regulatory and / or economic penalties related to associated gas processing, disposal or reinjection may make the oil recovery project economically unfeasible.

While the Engal process produces LNG without the use of external refrigerants, the process inefficiently utilizes its limited refrigeration capacity upon the entire process stream without conjunctive use of multiple separation steps to offset this severe cooling requirement.

Furthermore, the Engal process inefficiently expands its process stream pressure to a level that results in a substantial and highly inefficient recompression of its flash gas.

However, the Foglietta process still requires at least one closed-loop refrigeration cycle comprising propane or propylene, both of which are explosive, not easily dispersed, and which must be stored and handled.

While the Dubar process is effective, it is relatively complex, utilizing a number of heat exchangers manifolded in series.

This higher pressure, heavier walled equipment adds substantial weight and expense to any commercial project.

The PLNG consumer will also require additional liquefaction, transport, and storage equipment to consume the PLNG, adding further cost to the supply and demand value chain.

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