FIELD: oil and gas industry.
SUBSTANCE: unit of low-temperature dephlegmation with rectification LTDR for complex gas treatment with LNG production, which includes inlet separator, low-temperature condensation unit with reducing devices, comprising first and second recuperative heat exchangers, a refluxer with a heat exchange section, connected by a reflux gas supply line equipped with a reducing device, with a low-temperature separator equipped with a line for outputting the prepared natural gas, as well as a condensate stabilization unit. Low-temperature separator is a demethanizer with a demethanised condensate feed line and a prepared natural gas discharge line equipped with a first recuperative heat exchanger, where one of the reducing devices is made in the form of an expander, on the dephlegmation gas supply line after the reducing device, there is a separator connected to the demethanizer by a residue separation supply line, on which there is a heat exchange section of the refluxer, and with LNG production unit – separation gas supply line, to which is adjoining line of its part supply in line of separation residue supply, wherein condensate discharge lines from inlet separator and dephlegmator with reducing devices, as well as a supply line of the first part of demethanized condensate, heated in the second recuperative heat exchanger, are connected to the demethanizer, and on the supply line of its second part as a stabilization unit a debutanization unit is installed, equipped with product output lines, further, the LNG production unit includes the carbon dioxide purification unit, the first compressor, the first cooler, the drying unit, the second cooler, the recovery heat exchanger, an expander and an LNG separator with an LNG outlet line and a return gas supply line to the prepared natural gas discharge line, on which the recovery heat exchanger and the second compressor are located, wherein the first refrigerator is equipped with the external coolant inlet/outlet lines, and the second one is by the input/output lines as the coolant part of the prepared natural gas or the part of the demethanized condensate from the demethanizer, and first and second compressors are connected to LNG producing unit expander and to at least one of expanders of low-temperature condensation unit by means of kinematic or electric connection.
EFFECT: production of LNG due to addition of LNG production unit, which compressors are connected to at least one of expanders, and refrigerator – with one of low-temperature process flows of low-temperature condensation unit, as well as high output of hydrocarbons C2+ by reducing the dephlegmator with reduced dephlegmation gas and avoiding formation of flare gases.
1 cl, 1 dwg
