LNG land bridge
An endless chain of elongated vehicles, each carrying a thermally insulated sealed container for liquefied gas (LNG) traveling at high speed along a guideway between loading and unloading locations. A folding mechanism turns vehicles into dense vertical side-by-side relationship for loading and unloading at low speed, similar to filling bottles by conventional bottling machines. Containers are connected to piping which recovers and returns in transit re-gasified LNG for re-liquefaction. Containers are capable of holding gas under pressure in case of extended conveyor stoppage. High vehicle speed is enhanced with magnetic levitation suspension and linear induction motor propulsion.
The present invention relates to design and construction of an endless chain of elongated vehicles, each carrying an elongated sealed container for liquefied gas (LNG). More specifically it relates to vehicle and container design, method of loading, unloading and transporting LNG safely and without undue re-gasification or boil-off loss in transit. Furthermore, container design and attached piping feature recovery and recycling of in transit re-gasified fluid. In general, liquefaction plants liquefy gas by cooling it to below −260° F. (−160° C.). Elongated containers are then dynamically loaded with LNG while in side-by-side upright position, similar to filling bottles by conventional bottling machines. Thereafter, containers are sealed, rotated by their vehicles into horizontal end-to-end position and rapidly transported to their destination where they are returned into the same side-by-side upright position for unloaded. Any in transit re-gasified LNG, which may occur during extended conveyor stoppage is recovered and returned for re-liquefaction by a to vehicles attached flexible endless gas return pipeline.
SUMMARY OF THE INVENTIONThe present invention provides the ability to carry LNG by a conveyor of a type having in a closed loop an endless string of elongated vehicles containing cylindrical containers traveling at relatively high rate of speed between a loading end and an unloading end, vehicles with containers being folded into dense vertical side-by-side relationship at relatively low rate of speed for loading at a loading end and for unloading at an unloading end. Containers are heat insulated and can carry contents under pressure. When in densely folded upright relationship, vehicles with containers reveal two access ports, one at the top for fluid loading and unloading, and one on the side for returned gas release. Containers are equipped with safety pressure release valves, which are connected to an attached endless flexible gas return pipe. Discharge of gas from containers is returned for re-liquefaction by a flexible gas return pipe. The box-shaped vehicles have suspension, guidance and propulsion means for high-speed travel along guideways. Vehicles are paired and coupled together by couplings so that two adjacent access ports face each other. There are two types of couplings, one with wing-like cam followers near their upper edge, which are located at the access port ends of the vehicles, and one with wing-like cam followers near their bottom edge, which are located at the opposite ends of the vehicles. Vehicles have attached on each side a row of permanent magnets magnetized in vertical direction. High-speed sections of the guideway consist of up-facing U-shaped channels having near the top of each channel leg matching rows of permanent magnets magnetized in opposite direction to those on vehicles. Suspension of vehicles thus occurs by magnetic repulsion between vehicle magnets and guideway magnets. Dual guide channels in guideway and guideway followers on the vehicles provide lateral guidance. Propulsion is by linear induction motors, the primary of which is located at intervals in the bottom center of the U-shaped guideway channel. The underside of vehicles is covered by platens, which act as linear motor secondary. The cam followers on the couplings engage stationary dual cams before and after each loading and unloading location whereby vehicles are rotated from end-to-end relationship to side-by-side relationship and back. While in side-by-side relationship, vehicles are held against, and rotate with, loading and unloading carousels, at which time containers and the flexible gas return line is accessed for loading and unloading. The flexibility of the endless gas return pipe allows it to bend with containers when they fold and unfold at loading and unloading ends. Said LNG conveyor comprising:
(a) means for carrying LNG in heat insulated pressure containers;
(b) means for dynamic loading and unloading containers;
(c) means for in transit re-gasified LNG to be recovered for re-liquefaction;
(d) means for guiding and propelling containers along guideways.
The present invention is intended to enable transportation overland of LNG in large quantities, similar to what is already commonly done by ship at sea. The advantage of liquefaction is that gas volume is thereby reduced by a ratio of about 620 to one. While LNG ships take many days for a single delivery, they have on board refrigeration machines to prevent re-gasification of their cargo. Re-gasification expands LNG back to its original volume, except when it is confined in pressure containers. The present invention has no refrigeration machines traveling with its containers. Instead it relies on delivering LNG at high rate of speed, thereby leaving very little time for temperature increase and LNG re-gasification in transit. To enable high speed, means of suspension consist of permanent magnets in repulsion, and means for propulsion consist of linear induction motors.
Large quantities of stranded natural gas in remote regions could be brought as LNG to market with this invention, for example, from the North Slope of Alaska for a distance of 800 miles (1,300 Km) to a shipping port in the south of Alaska. With a line speed of 200 miles/hour (320 Km/hour), containers would be exposed for four hours to LNG re-gasification inducing surroundings, which with pre-cooling of LNG to lower than re-gasification temperature and with good insulation would keep heat intrusion and re-gasification to a minimum. However, the present invention provides that any emitted gas due to re-gasification and excessive container pressure would be recovered and returned for re-liquefaction by the endless flexible gas return pipe to which all containers are connected. No gas would be released to the outside.
For a shorter application, the present invention could also be used as an LNG Land Bridge across Panama similar to what already exists there for crude oil. Many new LNG ships are now also too large to fit through the Panama Canal. LNG re-gasification while in transit may also be reduced or even totally avoided by (1) pre-cooling containers before filling, (2) filling containers only partially and (3) replacing long conveyors with shorter ones interspaced with liquefaction booster plants.
The best mode of carrying out the present invention is as follows:
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- 1. Elect capacity, design physical components for the elected capacity and perform full size tests.
- 2. Erect an elevated triangular truss support structure along the route and attach the LNG Land Bridge to its top.
- 3. Constructs LNG supply facilities at the loading end of the LNG Land Bridge,
- 4. Construct LNG shipping facilities at the unloading end of the LNG Land Bridge.
Claims
1. A method for transporting liquefied gas (LNG) between loading and unloading locations in end-to-end connected elongated thermally insulated sealed container carrying vehicles, guided and propelled in a closed loop having vehicle folding and unfolding means to achieve a low rate of speed for loading and unloading, and a high rate of speed in-between.
2. A method of claim 1 wherein incidentally re-gasified portions of LNG from containers and incidentally to loading and unloading emitted gas is recovered for re-liquefaction.
3. A method of claim 2 wherein containers are connected through pressure release valves to an attached endless flexible gas return pipe.
4. A device for transporting liquefied gas (LNG) between a loading and unloading location in end-to-end connected elongated thermally insulated sealed container carrying vehicles, guided and propelled in a closed loop having vehicle folding and unfolding means to achieve a low rate of speed for loading and unloading, and a high rate of speed in-between, said device comprising:
- (A) each vehicle providing for guidance, propulsion, controls and connection to adjacent vehicles;
- (B) containers in vehicles having gas and LNG access port for mating with loading and unloading nozzles at loading and unloading locations;
- (C) means at loading and unloading locations for supplying to, and withdrawing from, containers through flexible temporary hookups gas and LNG.
5. A device of claim 4 wherein incidentally re-gasified portions of LNG from containers and incidentally emitted gas during filling and discharge is recovered for re-liquefaction.
6. A device of claim 4 wherein containers are connected through pressure release valves to an attached endless flexible gas return pipe.
Type: Application
Filed: Aug 31, 2006
Publication Date: Mar 6, 2008
Inventor: Ernst G. Knolle (So. San Francisco, CA)
Application Number: 11/512,960