Integrated cascade process for vaporization and recovery of residual LNG in a floating tank application

Patent metadata

Field	Value
Publication number	US-9835373-B2
Application number	US-201414280134-A
Country	US
Kind code	B2
Filing date	May 16, 2014
Priority date	Jun 17, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

Methods and systems for vaporizing and recovering LNG are provided. One method includes: a) heating at least a portion of the LNG to provide a boil-off gas stream and a liquid quench stream; b) routing the boil-off gas stream and the liquid quench stream to a quench system, wherein the quench system cools the boil-off gas stream to provide a quenched stream; and c) compressing the quenched stream to provide a compressed quenched stream.

First claim

The invention claimed is:

1. A method for vaporizing liquefied natural gas (LNG) produced from a main liquefaction process and stored in an LNG storage tank comprising:
a) heating via a warm predominantly methane stream at least a portion of the LNG to provide a boil-off gas stream and a liquid quench stream;
b) routing the boil-off gas stream and the liquid quench stream to a quench system, wherein the quench system cools the boil-off gas stream to provide a quenched stream;
c) compressing the quenched stream to provide a compressed quenched stream, wherein a first part of the compressed quenched stream is routed to the main liquefaction process; and
d) heating a second part of the compressed quenched stream to provide a warm compressed quenched stream wherein the warm compressed quenched stream is the warm predominantly methane stream used to heat the LNG; wherein the warm predominantly methane stream is used as a refrigerant in a refrigeration cycle of the main liquefaction process.

2. The method of claim 1 wherein the first part of the compressed quenched stream is routed to a low-stage methane compressor of the main liquefaction process.

3. The method of claim 1 wherein the quench system is a compressor suction drum.

4. The method of claim 1 further comprising: routing boil-off gas originating from an LNG carrier to the quench system.

Assignees

• Conocophillips Co

Inventors

• Davies Paul Raymond
• Harris Jr James Lee

Classifications

• F25J2290/62

  Details of storing a fluid in a tank · CPC title

• F25J1/0025

  Boil-off gases "BOG" from storages · CPC title

• F17C2227/0157

  Compressors · CPC title

• F25J1/0052

  by vaporising a liquid refrigerant stream · CPC title

• F25J1/0209

  as at least a three level refrigeration cascade · CPC title