Discharge of liquified natural gas at offshore mooring facilities

Abstract

A method and arrangement for transferring liquified natural gas from a seagoing tanker to an on-shore facility including boosting the pressure of the liquefied natural gas to above the critical pressure and passing the liquefied natural gas through a heat exchanger immersed into the sea thereby heating the gas to near ambient temperature.

1 . A method of transporting liquified natural gas from a seagoing tanker to an on-shore facility, comprising: 
 providing a source of liquified natural gas on the tanker;    filling a riser configured to accept the liquified natural gas from the tanker with liquified natural gas;    delivering the liquified natural gas on the tanker to a sub-sea pump via the riser;    boosting the pressure of the liquified natural gas transported from the tanker to above a critical pressure of the natural gas; and    passing the liquified natural gas through a heater to achieve a near ambient temperature of the natural gas.    
   
   
       2 . The method of transporting liquified natural gas according to  claim 1 , further comprising: 
 reducing the pressure in the riser before filling the riser with the liquified natural gas from the tanker.    
   
   
       3 . The method of transporting liquified natural gas according to  claim 1 , wherein the sub-sea pump is in a cryogenic insulated pressure vessel.  
   
   
       4 . The method of transporting liquified natural gas according to  claim 1 , wherein the step of passing the liquified natural gas through the heater is performed through pipes buried in the seabed.  
   
   
       5 . The method of transporting liquified natural gas according to  claim 1 , wherein the step of passing the liquified natural gas through the heater is performed through pipes floating one of on and above the seabed.  
   
   
       6 . The method of transporting liquified natural gas according to  claim 1 , further comprising: 
 passing the liquified natural gas through a heater on shore.    
   
   
       7 . An arrangement for transporting liquified natural gas from a sea-going vessel to shore, comprising: 
 a sub-sea delivery pipeline configured to accept natural gas from the sea-going vessel;    a heater connected to the sub-sea delivery pipeline, the heater configured to raise a temperature of the liquified natural gas to a near ambient temperature;    a sub-sea booster pump connected to the heater by a pipe, the pump configured to accept the liquified natural gas from the vessel;    a pipeline end manifold connected to the sub-sea booster pump; and    a flexible riser connected to the pipeline end manifold configured to accept fluid from the sea-going vessel.    
   
   
       8 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the manifold is configured on the sea bed.  
   
   
       9 . The arrangement for transporting liquified natural gas according to  claim 7 ,. further comprising: 
 a suction pipe configured between the pipeline end manifold and the pump.    
   
   
       10 . The arrangement for transporting liquified natural gas according to  claim 9 , further comprising: 
 a check valve in the suction pipe.    
   
   
       11 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the riser is made of metal.  
   
   
       12 . The arrangement for transporting liquified natural gas according to  claim 7 , further comprising: 
 a cryogenic insulated pressure vessel connected to the pipeline end manifold to accept liquified natural gas, wherein the sub-sea booster pump comprises a first pump which is placed in the cryogenic insulated pressure vessel, the first pump configured to pump liquified natural gas stored in the vessel to the heater.    
   
   
       13 . The arrangement for transporting liquified natural gas according to  claim 12 , wherein a suction for the pump is at a low point in the cryogenic insulated pressure vessel.  
   
   
       14 . The arrangement for transporting liquified natural gas according to  claim 7 , further comprising: 
 a second pump placed in the cryogenic insulated pressure vessel, the second pump configured with an inlet at an approximately center position of the vessel and a discharge positioned in the vessel through a discharge pipe connected to the heater.    
   
   
       15 . The arrangement for transporting liquified natural gas according to  claim 14 , wherein the second pump has a lesser pumping capacity than the first pump.  
   
   
       16 . The arrangement for transporting liquified natural gas according to  claim 14 , wherein the second pump is configured to pump both a liquid and vapor phase.  
   
   
       17 . The arrangement for transporting liquified natural gas according to  claim 12 , wherein the vessel has check valves preventing a backflow of fluid.  
   
   
       18 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein pipes for the heater are immersed in the sea and supported above the seabed.  
   
   
       19 . The arrangement for transporting liquified natural gas according to  claim 18 , wherein the pipes for the heater are made of one of stainless steel, INVAR, aluminum and titanium.  
   
   
       20 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger pipe is buried below the seabed.  
   
   
       21 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger pipe is comprised of more than one parallel pipes.  
   
   
       22 . The arrangement for transporting liquified natural gas according to  claim 7 , further comprising: 
 a heater on-shore configured to heat the natural gas.    
   
   
       23 . A method of transporting liquified natural gas from a seagoing tanker to an on-shore facility, comprising: 
 maintaining at least one pump in a temperature range so that acceptance of liquified natural gas will not damage the at least one pump;    docking a ship to a riser;    connecting an outlet for a liquified natural gas on the tanker to the riser;    providing a source of the liquified natural gas on the tanker to the riser;    delivering the liquified natural gas via the riser to a pump;    boosting the pressure of the liquified natural gas to above a critical pressure for the natural gas by the pump; and    passing the liquified natural gas through a heater immersed in the sea to heat the natural gas.    
   
   
       24 . The method according to  claim 23 , wherein the pump is positioned in a cryogenic vessel.  
   
   
       25 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger pipe is supported by submerged buoys.  
   
   
       26 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger pipe is configured in one of a circle and spiral.  
   
   
       27 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger pipe is configured in a helix.  
   
   
       28 . The arrangement for transporting liquified natural gas according to  claim 7 , wherein the heat exchanger is a single pipe.  
   
   
       29 . A system to transport liquified natural gas from a vessel comprising: 
 a riser connected to the vessel;    a manifold connected to the riser;    a pump assembly connected to the manifold; and    a heat exchanger connected to the pump assembly;    a manifold connected to the heat exchanger, and    a delivery pipeline connected to the manifold.    
   
   
       30 . The system to transport liquified natural gas according to  claim 29 , wherein the manifold is connected to pipes of the heat exchanger, wherein control valves permit regulation of natural gas flow from the heat exchanger.  
   
   
       31 . The system to transport liquified natural gas according to  claim 30 , wherein the manifold is connected to pipes of the heat exchanger, wherein the control valves regulate the flow in response to a temperature of the natural gas at the control valves.  
   
   
       32 . The system to transport liquified natural gas according to  claim 29 , wherein the pumping assembly further comprises a tank configured to accept liquified natural gas.  
   
   
       33 . The system to transport liquified natural gas according to  claim 29 , wherein the heat exchanger is configured of pipes being shaped substantially into spirals.  
   
   
       34 . The system to transport liquified natural gas according to  claim 31 , wherein the heat exchanger pipes are anchored to the seabed.  
   
   
       35 . The system to transport liquified natural gas according to  claim 34 , wherein the heat exchanger pipes are supported by buoys.  
   
   
       36 . The system to transport liquified natural gas according to  claim 35 , wherein the buoys are connected to the pipes through chains.  
   
   
       37 . The system according to  claim 29 , wherein the heat exchanger has pipes which have at least one of a vortex suppression configuration and a heat transfer configuration.  
   
   
       38 . The system according to  claim 29 , wherein the heat exchanger is protected against encroaching vessels by a protective structure erected in the sea surrounding the heat exchanger  
   
   
       39 . A system to deliver liquified natural gas from a sea-going tanker, comprising: 
 a transporting arrangement for delivering the liquified natural gas from the sea-going tanker;    a cryogenically maintained pumping arrangement configured to accept liquified natural gas from the transporting arrangement and to raise the pressure to above the pressure of the receiving pipeline; and    a heat exchanger configured to take heat directly from the sea to warm the liquified natural gas.    
   
   
       40 . The method according to  claim 39 , further comprising: 
 warming the natural gas after delivery to shore from the heat exchanger.