METHOD AND DEVICE FOR LOW-TEMPERATURE SEPARATION OF GAS INTO FRACTIONS Russian patent published in 2007 - IPC F25J3/00 

FIELD: mechanical engineering.

SUBSTANCE: method comprises compressing the initial gas, cooling the gas, and separating the gas into fractions. The first stage of cooling of the initial gas is performed before compression, and the compression and second stage of the cooling is performed with a free-piston expander. The expansion cycle is performed in the regime of the cyclic pressure drop with generating hot and cold flows in above-piston and under-piston spaces, respectively. The hot compressed flow is discharged during the pressure rise. When the pressure drops, at least two or three cold flows containing hydrocarbon fractions are discharged. The cooling is performed in two stages. In the first stage, the cooling is carried out simultaneously with the regeneration. The device comprises unit for separating the flow into fractions, compression unit, at least two cooling units, valving system for supplying and discharging the gas flows, and pipeline system. The unit for separating the gas flow into fractions has compression unit and at least two cooling units. The compression unit and the second cooling unit are made of a free-piston expander. The first cooling unit is mounted upstream of the free-piston expander. The valving system is mounted in the separating unit, made for permitting cyclic pressure drop.

EFFECT: simplified method and device.

30 cl, 9 dwg