BOG ventilation and combustion in re-liquefaction plants of LNG carriers

Xin Cheng, Azizur Rahaman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A liquefied natural gas (LNG) carrier is designed to transport LNG over a long distance. During transportation, the leakage of boil-off gas (BOG) along with poor ventilation can pose an explosion risk. The traditional method for dealing with the BOG is to burn the gas to power the ship. As an alternative method, re-liquefaction plants on board re-liquefy the vapours back to the cargo tanks. This project will characterize the technical issues associated with fire protection in a confined space where LNG boil-off re-liquefaction takes place and will demonstrate what the appropriate ventilation rate in an emergency is. In addition, the CFD software (ANSYS CFX) is applied to simulate the ventilation and burning of boil-off gas in the on board re-liquefaction plant to ensure the safety of the cargo tanks for the worst case scenario. The traditional method for dealing with the boil-off gas (BOG) on board an LNG carrier is to burn the gas to power the ship. As an alternative method, re-liquefaction plants on board re-liquefy the vapour back to the cargo tanks [1]. In the last few years, the introduction of LNG re-liquefaction systems has given ship owners a choice of fuels and provides engine redundancy. Nevertheless, flammable natural gas is processed in both methods. Due to the inherent properties of a ship's structure, the re-liquefaction system, gas combustion unit, pipelines, etc. are located in the space enclosed under the deck. Under certain circumstances the leakage of natural gas, along with poor ventilation, can pose an explosion risk. Unfortunately, limited industry codes have been developed for fire protection in the cabin where the innovative LNG re-liquefaction system is located. The purpose of this project is to demonstrate the leaking and burning of boil-off gas in the on board re-liquefaction plant to ensure the safety of the cargo tanks for the worst case scenario by using CFD simulation software.

Original languageEnglish
Title of host publication2014 Oceans - St. John's, OCEANS 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479949182
DOIs
Publication statusPublished - 6 Jan 2015
Externally publishedYes
Event2014 Oceans - St. John's, OCEANS 2014 - St. John's, Canada
Duration: 14 Sep 201419 Sep 2014

Other

Other2014 Oceans - St. John's, OCEANS 2014
CountryCanada
CitySt. John's
Period14/9/1419/9/14

Fingerprint

Liquefaction
Liquefied natural gas
Ventilation
Gases
Ships
Fire protection
Explosions
Natural gas
Computational fluid dynamics
Vapors
Leakage (fluid)
Redundancy
Pipelines
Engines

Keywords

  • Boil-off Gas (BOG)
  • CFD
  • Liquefied Natural Gas (LNG) Carrier
  • Re-liquefaction Plant
  • Safety

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Ocean Engineering
  • Computer Networks and Communications

Cite this

Cheng, X., & Rahaman, A. (2015). BOG ventilation and combustion in re-liquefaction plants of LNG carriers. In 2014 Oceans - St. John's, OCEANS 2014 [7003288] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/OCEANS.2014.7003288

BOG ventilation and combustion in re-liquefaction plants of LNG carriers. / Cheng, Xin; Rahaman, Azizur.

2014 Oceans - St. John's, OCEANS 2014. Institute of Electrical and Electronics Engineers Inc., 2015. 7003288.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Cheng, X & Rahaman, A 2015, BOG ventilation and combustion in re-liquefaction plants of LNG carriers. in 2014 Oceans - St. John's, OCEANS 2014., 7003288, Institute of Electrical and Electronics Engineers Inc., 2014 Oceans - St. John's, OCEANS 2014, St. John's, Canada, 14/9/14. https://doi.org/10.1109/OCEANS.2014.7003288
Cheng X, Rahaman A. BOG ventilation and combustion in re-liquefaction plants of LNG carriers. In 2014 Oceans - St. John's, OCEANS 2014. Institute of Electrical and Electronics Engineers Inc. 2015. 7003288 https://doi.org/10.1109/OCEANS.2014.7003288
Cheng, Xin ; Rahaman, Azizur. / BOG ventilation and combustion in re-liquefaction plants of LNG carriers. 2014 Oceans - St. John's, OCEANS 2014. Institute of Electrical and Electronics Engineers Inc., 2015.
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