METHOD FOR PARTIAL LIQUEFACTION OF NATURAL GAS Russian patent published in 2013 - IPC F25J1/00 

FIELD: machine building.

SUBSTANCE: method includes separation of a high pressure natural gas flow into process and product flows. The product flow is dried and cleaned from CO₂, serially cooled in preliminary, main and additional heat exchangers, the produced steam and liquid mixture is throttled and separated into steam and liquid phases with subsequent direction of non-condensed natural gas into the return flow. The process flow of gas is dried, cooled, then expanded in the throttling valve of the first stage, then additionally cooled and expanded in the throttling valve of the second stage and mixed with the return flow of the non-condensed natural gas heated in the additional heat exchanger. Gas temperature upstream the throttling valve of the second stage is selected as minimum permissible, at which no crystallisation of CO₂ takes place after passage of gas via the throttling valve of the second stage.

EFFECT: invention makes it possible to increase efficiency and reliability of process of liquefaction of natural gas, having in its initial composition high content of carbon dioxide, and also to reduce share of highly boiling components in liquefied natural gas.

2 dwg