Process Description Feedstock - ethane-rich NG is dehydrated in unit 1 and divided into two streams. The first one is cooled in heat exchanger 3, the second one - in cooling unit 2, the compressor of which is coupled to expanders. Then the streams are combined, pressure is reduced in expander 4 and separated into condensate and gas in the separator 8. The condensate pressure is reduced by means of a liquid expander 7, and gas is fed to refluxer 9. The refluxer 9 is cooled by low-pressure gas, which is supplied from demethanizer 10. Further , the low-pressure gas is heated in heat exchanger 3 and removed from the plant. From the refluxer overhead 9, the reflux gas is removed and pressure is reduced in expander 5, and reflux is removed from the bottom, pressure is reduced using a liquid expander 6 and together with the pressure reduced condensate is fed into the demethanizer 10. Reflux is circulated between unit 2 and demethanizer 10 to ensure the reliability of fractionation. Low-pressure gas, LNG and NGL are discharged from demethanizer 10, and then are supplied to unit 11. From unit 11, the methane-rich gas is returned to demethanizer 10, and hydrocarbons C 2+ are removed from the plant.
Process features
Deep extraction of hydrocarbons C2+ by low temperature condensation and refluxing
LNG production with minimal capital costs
Low capital investment and operating costs
Technical Specification
NG Temperature: 5 - 25 °С
NG pressure 5,5 - 10,0 MPa
NG capacity up to 1 250 000 nm³/hour
Products: DSG, LNG of "A" or "B" brands, ethane fraction of "A" brand, NGL of "A" brand or Autogas or narrow fractions of hydrocarbons
С3+ fraction recovery up to 99.9%
Ethane recovery up to 98%
LNG extraction up to 6% of NG
Patents of the Russian Federation No. 2699910, 2731709, 2752063