Abstract: An apparatus for re-liquefying boil-off gas produced by liquid natural gas is described. The apparatus is made up of a collector, wherein the collector contains liquid natural gas, at least one first pump, wherein the first pump is in or adjacent to the liquid natural gas collector, a compressor, wherein the compressor communicates with the liquid natural gas (LNG) collector by a first conduit, at least one mixing device, wherein the mixing device communicates with the compressor by a second conduit, and wherein the mixing device communicates with the first pump by a third conduit, at least one separating device, wherein the separating device communicates with the mixing device by a fourth conduit, and wherein the separating device also communicates with the liquid natural gas (LNG) collector by a fifth conduit.