Energy Bridge Regasification Vessels, or EBRVs^®, are purpose-built LNG tankers that incorporate onboard equipment for the vaporization of LNG and delivery of high pressure natural gas. These vessels load in the same manner as standard LNG tankers at traditional liquefaction terminals, and also retain the flexibility to discharge in three distinct ways. These are:

  as liquid at a conventional LNG receiving terminal,

  as a gas through the EBRV’s connection with a subsea buoy in the hull of
  the ship, and

  as a gas through a high pressure gas manifold located forward of the
  vessel’s LNG loading arms.

Specialized Equipment

To accomplish the task of offshore LNG vaporization, EBRVs are designed to incorporate certain equipment and processes onboard, consisting of the five major components as listed below.

  High pressure cryogenic pumps – bring the LNG from the cargo tanks up to
  pressure prior to vaporization.

  Shell-and-tube vaporizers – convert the LNG back to vaporous natural gas.

  Oversized boiler - provides the steam and power necessary to sustain
  vessel operations and the shipboard regasification process.

  STL buoy compartment - designed to accommodate a submerged turret
  loading (STL) buoy system, which serves as the mooring system for
  the vessel.

  Reinforced LNG tanks and pump tower – designed to withstand the
  sloshing loads encountered throughout all loading levels while at sea

Vaporization of LNG

To accomplish the task of offshore LNG vaporization, EBRV’s may be operated in one of three ways as described below:

  Closed-Loop mode – steam from the EBRV’s boilers is used to heat fresh
  water circulated through the shell-and-tube vaporizers in the regasification
  plant. This results in minimal usage of seawater by the EBRV.

  Open-Loop mode – relatively warm sea water is drawn in through the
  EBRV’s sea chests. This warm seawater is used as a heat source
  and passed through the tubes of the shell-and-tube vaporizers causing
  the vaporization of the LNG. During this process the temperature of the
  seawater is lowered by approximately 13 degrees Fahrenheit (7 degrees
  Celsius). For this reason, the Open-Loop mode is not applicable for water
  temperatures below 45 degrees Fahrenheit.

  Combined Mode – seawater at temperatures between 45 and 58 degrees
  Fahrenheit can be used when heated by steam from the EBRVs boilers to
  provide sufficient heat for the vaporization of the LNG.

The maximum rate of discharge of the natural gas from an EBRV into the deepwater port will be determined by a combination of the availability of capacity on downstream pipelines and the regasification capabilities of the facilities located on-board each EBRV.