Patent ID: 7673476

Claim:
A compact and modular apparatus for refrigerating and liquefying a gas such as pure methane or a natural gas stream rich in methane, the apparatus comprising: a. a pre-compressor for compressing a low pressure, well-head gas stream to a high pressure compressed main feed stream at a pressure of between about 1500 psig and about 3500 psig and at near ambient temperature; b. a means for cooling the compressed main feed stream to a temperature of between about −10° F. to about −100° F.; c. a first expansion means configured to expand the cooled, compressed feed stream to form a first bi-phase stream comprising a first refrigerated vapor component and a first liquid component; d. a primary separation tank configured to separate the first refrigerated vapor component and the first liquid component; e. a second expansion means configured to connect directly to the primary separation tank, with no cooling means located between the first and second expansion means, to directly expand the separated first liquid component to form a second bi-phase stream comprising a second refrigerated vapor component and a second liquid component; f. a secondary separation tank configured to separate the second refrigerated vapor component and the second liquid component; and g. a means configured for storage and transport of the separated second liquid component, wherein the apparatus is compact and modular and adapted for transport from one natural gas site to another.