Process Description Feedstock – dry NG – is separated in separator 1 into water condensate and gas, which is separated into two streams. The first stream is supplied as a heat transfer medium to heater of demethanizer 5, where it is cooled, and mixed with the second stream cooled in heat exchanger 2. The combined stream pressure is reduced by device 11 and supplied into demethanizer 5, from the bottom of which the C₂₊ fraction is output to the fractionation unit 10. Hydrocarbon fractions and methane-containing gas are removed from unit 10. The methane fraction is removed from the top of demethanizer 5, which is separated into two streams. The first stream enters the column heater 6 as a heat transfer medium and mixes with the second stream cooled in heat exchanger 3. The combined stream pressure is reduced by device 12 and supplied into column 6, from the top of which the nitrogen-containing gas is discharged and separated into two streams. The first stream enters the heater of the column 7 as a heat transfer medium, mixes with the second stream cooled in heat exchanger 4, and is supplied into column 7. Helium concentrate is removed from the top of column 7, and liquefied gas is removed from the bottom. The liquefied gas pressure is reduced by device 14, heated in the refluxing section of the column 7, heat exchangers 4, 3, 2 and removed from the unit. From the bottom of column 6, high-pressure LNG is discharged, which is reduced by device 13, heated in the refluxing section of the column 6 and separated in separator 8 into natural gas and low- pressure LNG. The latter is pumped out by pump 9. Both streams are heated in heat exchangers 3, 2 and removed from the unit.
Process features
The use of film columns with variable reflux and vapor ratio for the purpose of deep heat/cold recovery of process streams
The possibility of simultaneous production of LNG
A significant reduction in equipment quantity
Low capital investment
Technical Specification
Raw NG pressure is 8.0-12.0 MPa
Unit capacity of up to 10 million nm³/day of commercial gas
Extraction of GC and С₃-С₄ 100 %, ethane of up to 99,5 %, methane of up to 99 % of the potential
Production of helium concentrate with helium extraction up to 99 % of the potential.
Patents of the Russian Federation No. 2733710, 2733711, 2739754, 2736682.