Natural gas treatment with dry stripping gas circulation (cycling process)

Process Description
Feedstock – dry NG – is separated in the separator 1 into a residue, which is sent to the fractionation unit 8, and gas, which is separated into three streams. The first stream is supplied as a heat transfer medium to heater of demethanizer 5, where it is cooled, mixed with the second stream cooled in the heat exchanger 2. The mixed stream pressure is reduced in expander 6 and supplied into demethanizer 5. The third NG stream is sequentially cooled in heat exchangers 4 and 3, compressed by compressor 7, which is connected to expander 6. The compressed gas is heated in heat exchanger 4 and sent for injection into the reservoir of the field. Demethanized condensate from the bottom of demethanizer 5 is supplied into unit 8, from which hydrocarbon fractions are removed. The treated NG is removed from the top of demethanizer 5, heated in heat exchanger 3, part of the NG stream is directed to the unit 8. Next, the heated NG is mixed with methane-containing gas removed from unit 8, heated in heat exchanger 2 and sent to the gas pipeline or consumers.

Process features

• No need to use external sources of cold
• Minimization of methanol losses
• Elimination of process discharges to the flare

Technical Specification

• Raw NG pressure is 4.0–12.0 МPа
• Applicable for the line of CGTU with unit capacity of up to 10 million nm³/day of commercial gas
• Gas condensate withdrawal up to 99.9% of the potential
• Сapacity propane-butane fraction withdrawal up to 75-85%

Patents of the Russian Federation No.
2757211, 2753751

Development level, industrial application
Developed design concepts
Completed feasibility study