Method for producing a flow rich in methane and a flow rich in C2 + hydrocarbons, and associated installation

An installation for producing a flow rich in methane and a flow rich in C2+ hydrocarbons from a supply flow containing hydrocarbons, the installation comprising:

• a supply flow separator configured to separate the supply flow into a first fraction of the supply flow and at least a second fraction of the supply flow;
• a first heat exchanger configured to cool the first fraction of the supply flow;
• a first heat exchange introducer configured to introduce the first fraction of the supply flow into the first heat exchanger;
• a first separation flask and a first separation flask introducer configured to introduce the cooled first fraction of the supply flow into the first separation flask in order to produce a light upper flow and a heavy lower flow;
• a light upper flow divider configured to divide the light upper flow into a turbine supply fraction and a column supply fraction;
• a first distillation column;
• a turbine supply fraction pressure reducer configured to reduce a pressure of the turbine supply fraction comprising a first dynamic pressure reduction turbine and a first turbine introducer configured to introduce at least a portion of the fraction subjected to pressure reduction into the first turbine in a middle portion of the first distillation column;
• a column supply fraction processor configured to cool and at least partially to condense the column supply fraction comprising a second heat exchanger and a cooled column supply fraction pressure reducer configured to reduce pressure of the cooled column supply fraction and to introduce the cooled column supply fraction into an upper portion of the first distillation column;
• a heavy lower flow processing unit configured to pressure reduce and to partially vaporize the heavy lower flow comprising the first heat exchanger;
• a second separation flask and a second separation flask introducer configured to introduce the heavy lower flow into the second separation flask in order to produce an upper gas fraction and a lower liquid fraction;
• a pressure reducer configured to pressure reduce the lower liquid fraction and a first distillation column introducer configured to introduce the reduced pressure lower liquid fraction into the middle portion of the first distillation column;
• an upper gas fraction cooler and condenser unit configured to cool and at least partially to condense the upper gas fraction comprising the second heat exchanger and an introducer configured to introduce the upper gas fraction into the upper portion of the first distillation column;
• a lower column flow recovery unit configured to recover a lower column flow at the bottom of the first distillation column, and a former configured to form the flow rich in C2+ hydrocarbons from the lower column flow;
• an upper column flow recovery and reheating unit configured to recover and to reheat an upper column flow rich in methane, at the top of the first distillation column;
• a compressor unit configured to compress at least a fraction of the upper column flow comprising at least a first compressor coupled to the first dynamic pressure reduction turbine and at least a second compressor;
• a removal unit configured to remove from the reheated and compressed upper column flow an extraction flow,
• an introducer configured to introduce the extraction flow in the first and second heat exchanger and the cooled extraction flow into an upper portion of the first distillation column;
• a second dynamic pressure reduction turbine separate from the first dynamic pressure reduction turbine;
• a second turbine introducer configured to introduce at least a portion of the second fraction of the supply flow into the second dynamic pressure reduction turbine;
• an effluent former configured to form an effluent from the second dynamic pressure reduction turbine;
• the second heat exchanger being able to cool and at least partly liquefy at least a portion of the effluent from the second dynamic pressure reduction turbine in order to form a cooled reflux flow;
• and
• a reflux introducer configured to introduce the cooled reflux flow from the second heat exchanger into the first distillation column,
• wherein the portion of the second fraction of the supply flow introduced into the second dynamic pressure reduction turbine is conveyed from the separation point of the supply flow to the second dynamic pressure reduction turbine without passing through a heat exchanger.