Combined separation of heavy - and low boilers from natural gas

摘要

It is a method for the separation of heavy - and low boilers from a hydrocarbon - extend feed fraction, preferably made of natural gas, is described wherein the feed fraction (1), partially condensed (e1, e2), by rectification (t1) a high boilers - rich liquid fraction (8) is separated off (1. separating stage), the resulting, on which has been depleted heavies gas (10), partially condensed (e4) and by rectification (t2) in a methane - rich liquid fraction (11) and a low boilers - rich gas (12) is separated, (2. separating stage). According to the invention,– if the 1. separating stage (t1) at a pressure of at least 25 bar,– the depleted heavies is subjected to gas (10) before they are supplied to the separating stage (t2) 2. no pressure increase, and– , the return flow of 2. separating stage (t2) generated by an open cooling circuit,– the refrigeration cycle circulating refrigerant in the open on two different temperature levels barrel against the return currents (14, 15) in the top condenser (e7) and in a side condenser (e8) of the 2. separating stage (t2) is evaporated, and the pressure of the capacitor (e8) in the sides of the vaporized refrigerant (25) is at least three times, is so high as the pressure of the in the top condenser (e7) vaporized refrigerant (22).