A feed gas including neon, nitrogen, and helium is cooled in a heat exchange system to a first temperature to produce a two-phase mixture that is introduced into a first phase separator and separated into a nitrogen-rich liquid and a first gaseous crude neon stream. The pressure is reduced in at least a portion of the nitrogen-rich liquid, which is vaporized in the heat exchange system to generate a portion of the refrigeration therein. The first gaseous crude neon stream is introduced into a first adsorber that removes impurities such as nitrogen. The gaseous crude neon stream is further cooled to a second temperature. A portion of the cooling duty may come from the heat exchange system and another portion may come from a cryocooler to produce a two-phase stream. The two-phase stream is separated in a second phase separator into a crude helium vapor stream and a crude neon liquid stream with the latter being introduced into a distillation column to produce a vent stream containing a helium impurity and a pure liquid neon product. The pure liquid neon product is vaporized in the heat exchange system to generate refrigeration and produce the pure gaseous neon product.

A low-temperature device for separating and purifying gas based on a small-sized low-temperature refrigerating machine includes a primary, secondary and quaternary heat exchanger, at least one small-sized low-temperature refrigerating machine, and at least one liquid collecting tank. The small-sized low-temperature refrigerating machine includes a first cold head and a second cold head, the secondary heat exchanger is provided on the first cold head to form a primary cold head heat exchanger, the quaternary heat exchanger is provided on the second cold head to form a secondary cold head heat exchanger, a mixed gas outlet is connected to an inlet of the primary cold head heat exchanger. By using primary and secondary cold heads of the small-sized low-temperature refrigerating machine as cold sources, gases having different condensing temperature are liquefied and solidified separately, and two or more gases can be separated and purified at a lower cost.

The present invention relates to a cryocooler suitable for gas liquefaction applications, that comprises a coldhead with one or more refrigeration stages; further comprising: a refrigerator compressor for distributing compressed gas-phase cryogen inside the coldhead; a heat exchanging coil arranged at least partially around the external region of the coldhead; at least one extraction orifice communicating a gas circulation circuit inside the coldhead with the heat exchanging coil; acting said extraction orifice/s as pass-through port/s which allow the gas inside the coldhead to flow through the inside of the heat exchanger coil for exchanging heat with the exterior thereof, and wherein the heat exchanging coil is adapted to connect and redirect the gas to one return port connected to the gas circulation circuit. Another object of the invention relates to a cryogen-gas liquefaction system and a method for liquefaction of gases that comprises said system.