Systems and methods for distributed production of liquified natural gas

Abstract

This disclosure teaches systems and methods for distributed production of liquefied natural gas by utilizing refrigeration to reach the condensation of natural gas, removing of compression heat loads, sensible heat loads, and latent heat at ambient temperatures utilizes the Stirling cycle, both refrigeration and thermal heating processes, for enabling cryogenic refrigeration and the portable production of LNG. Generally, the natural gas may be supplied from existing or nearby pipelines and the LNG production system itself may be powered by electric motors or internal combustion engines. The refrigeration machine/LNG production system may be installed at, within or nearby to existing or new construction gas stations for refueling of all classes of motorized vehicles. Additional embodiments include the refrigeration machine installed into standard over-seas containers for LNG import or export, as well as any other portable platform for distributed LNG production.

What is claimed is: 
     
         1 . A method for converting natural gas to liquid natural gas, the method comprising the following steps:
 receiving natural gas into a cowling through one or more input valves, said cowling adapted to receive a stirling engine and having at least one heat transfer surface, said at least one heat transfer surface in direct contact with a cool head of said stirling engine such that heat is transferred from said natural gas to said heat transfer surface and then to said cool head of said stirling engine, thereby converting said natural gas into said liquid natural gas; and   outputting said liquid natural gas from said cowling through one or more output valves.   
     
     
         2 . The method of  claim 1 , wherein said LNG is outputted from said cowling through at least one of said output valves to at least one storage tank, at least one of said storage tanks comprising at least one level sensor, said at least one level sensor detecting the level of LNG contained in said at least one of said storage tanks; and
 adjusting a rate or volume of LNG outputted through said cowling in response to said at least one level sensor.   
     
     
         3 . The method of  claim 1 , having at least two level sensors, said at least two level sensors comprising a high level sensor and a low level sensor. 
     
     
         4 . The method of  claim 1 , said method running in automatic mode thereby producing LNG uninterrupted unless a trigger actions occurs. 
     
     
         5 . The method of  claim 4 , wherein said trigger action is one or more of:
 main storage tank becomes full;   manual commands to stop operations;   any system failures;   safety or power issues; and   engine alarm for low coolant, low oil pressure, or low working gas pressures.   
     
     
         6 . The method of  claim 1 , having at least two output valves, said two output valves comprising at least one LNG output valve and at least one bleed valve, wherein if a build of up of frozen materials impedes said heat transfer, said method additionally comprises the following steps:
 closing all of said one or more input valves thereby stopping said natural gas from entering said cowling;   closing all of said at least one LNG output valves;   opening said at least one bleed valve;   reversing said stirling engine such that heat is transferred from said cool head of said stirling engine to said heat transfer surface thereby melting said frozen material, said melted material exiting said cowling via said bleed valve.