UNIVERSAL GAS SEPARATION AND LIQUEFACTION METHOD (VARIANTS) AND DEVICE Russian patent published in 2006 - IPC F25J3/02 F25J1/02 

FIELD: gas conditioning, separation and liquefaction, particularly for natural gas in oil industry.

SUBSTANCE: method involves treating gas; separating thereof in membrane or cryogenic gas-separation unit; liquefying and separating gas in liquefying unit. Gas treatment includes cleaning gas of water droplets and mechanical injuries and supplying the cleaned gas to gas-separation unit inlet. Then natural gas is cleaned and supplied through gas distribution means to gas-separation vessels which increase methane concentration to 99.9%. Methane moves to gas liquefying unit inlet. Nitrogen and hydrocarbons are separated in serially connected gas-separation vessels into ethane, propane, butane and nitrogen. Ethane, propane and butane are directed to store means. Cryogenic unit is adapted for cleaned natural gas dividing into two flows, which are cooled, combined and then expanded. The expanded flow is supplied to rectification column. Flow of the first steam is cooled to -112°C - -150°C temperature to form vapor and liquid phases by passing the first steam through a row of heat exchangers in which the first steam is in counterflow with nitrogen flow circulating in cooling loop. The cooled flow of the first steam is separated into vapor and liquid phases to create flow of the second steam having methane and nitrogen ratio of 1:(1.0-2.0) and to create flow of the second liquid having methane and nitrogen ratio of 1:(4.0-2.0). Flow of the second liquid in phlegm form is returned to rectification column and the first liquid is removed from rectification column, wherein the first liquid is product having temperature exceeding -112°C. The product is directed to high-pressure natural gas store means and to liquefying unit, in which gas is separated inside de-methanizing, de-ethanizing, de-butanizing and de-propanizing columns. Then pressure and temperature of the gas flows exited from the columns are equalized and the flows are combined into single flow. Part of the flow is reduced and supplied to operator's compartment.

EFFECT: extended field of method and device application, increased device reliability and quality of obtained gases.

9 cl, 4 dwg, 1 tbl