FIELD: technological processes.
SUBSTANCE: invention relates to low-temperature separation plants and can be used in the gas industry for the separation of natural gas transported along main gas pipelines. Proposed installation in both versions includes a drying unit, a compressor, a refrigerator, three expansion units, a recuperative heat exchanger, a reflux condenser and a demethanizer. First option also includes a separator. In operation of the first embodiment, the high pressure natural gas is drained and divided into two streams, the first stream is cooled in a recuperative heat exchanger and the second is compressed, cooled, reduced by a first expander and combined with the first expander. Combined stream is reduced with a second expander and sent to a reflux condenser where it is refluxed by countercurrent cooling from the low pressure gas supplied from the separator, which is then heated in a recuperative heat exchanger, mixed with the adsorbent regeneration gas supplied from the drying unit and discharged from the unit. Resulting reflux gas after reduction in the third expander is fed to the separator together with the methane-containing gas from the demethanizer. Wide fraction of light hydrocarbons is withdrawn from the bottom of the separator, which is mixed with a reflux from the bottom of the reflux condenser and subjected to fractionation in a demethanizer to produce liquid hydrocarbons or ethane and propane-butane fractions. Operation of the second embodiment is characterized in that a wide fraction of light hydrocarbons is not released from the gas stream after the third expander, only the phlegm is sent to the demethanizer, and the methane-containing gas is mixed with a low-pressure gas.
EFFECT: increasing the yield of liquid hydrocarbons.
2 cl, 2 dwg
