Process for separating and recovering ethane and heavier hydrocarbons from LNG

Abstract

A process for extracting heavier components, e.g., NGL from liquid / fluid streams such as Rich LNG (RLNG) stream(s) with the streamlined economy. The process involves heating the RLNG stream in heat exchanger(s) (LNGX) against column overhead vapour stream; not requiring separation of Feed streams into feed and reflux by splitting either pre- or post- of heat LNGX. The source liquid RLNG is processed producing liquid NGL and at same time returning purified Lean LNG (LLNG) product in its Liquid LNG form. The process operates essentially without the need for compression equipment. The process further provides without compressors vaporized natural gas at pipeline pressure and specifications. This is a system that can flexibly change product compositions and specifications of product NGL / Lean LNG / Pipeline Gas and operate in both Pipeline Specification deep 99% Ethane (C2) Extraction and Ethane (C2) Rejection NGL recovery modes with economy of equipment and energy requirements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of the filing date of and priority to U.S. Provisional Application Ser. No. 61 / 405,192 entitled “A flexible high C2 (Ethane) Recovery or Rejection NGL Recovery Process for + / −1% and higher C2 rich LNG or Hydrocarbon fluid streams without need for compression / recompression to re-liquefy the Lean LNG” and filed Oct. 20, 2010, Confirmation No. 4779. Said application is incorporated by reference herein.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not Applicable.BACKGROUND OF THE INVENTION[0003]The present invention example relates to the field of processing gasses in a liquid or fluid phase such as for LNG (Liquified Natural Gas) and NGL (Natural Gas Liquids) as known in the oil and gas industry and the recovery of C2 and C2+ (ethane+) components from the hydrocarbon fluid streams. More particularly, the present invention relates to the recovery of ethane and less volatile compounds ...

AI Technical Summary

Benefits of technology

[0016]Then, the feedstock Rich LNG is heated within the heat exchanger while maintaining the feedstock Rich LNG below its bubble point to avoid vaporization while in the heat exchanger. In a preferred embodiment, the step of maintaining the feedstock Rich LNG below its bubble point to avoid vaporization while in the heat exchanger is achieved by regulating the pressure in the heat exchanger to maintain the Rich LNG in its liquid phase with no vaporization.

Problems solved by technology

Storage of LNG presents the problem of uncontrollable “roll overs” caused by density inversions.

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