Methods and systems for separating hydrocarbons

A method for separating hydrocarbons comprising the steps of:

• passing a feed gas stream to a distillation column, the feed gas stream comprising methane, ethane, and propane and heavier hydrocarbons;
• in the distillation column, separating the methane and the ethane from the propane and heavier hydrocarbons, thereby producing a residue gas stream comprising the methane and the ethane at an upper section of the distillation column and a natural gas liquids (NGL) stream comprising the propane and heavier hydrocarbons at a lower section of the distillation column;
• separating the NGL stream into a first portion and a second portion, withdrawing the first portion from the distillation column as a product NGL stream, heating the second portion in a reboiler of the distillation column, and returning the heated second portion from the reboiler to the distillation column;
• passing the residue gas stream to a compressor to produce a hot and compressed residue gas stream;
• and
• directing heat from the hot and compressed residue gas stream to the reboiler to perform the step of heating the second portion of the product NGL stream.

A system for separating hydrocarbons comprising:

• a distillation column that a) receives a feed gas stream comprising methane, ethane, and propane and heavier hydrocarbons and b) separates the methane and the ethane from the propane and heavier hydrocarbons to produce a residue gas stream comprising the methane and the ethane at an upper section of the distillation column and a natural gas liquids (NGL) stream comprising the propane and heavier hydrocarbons at a lower section of the distillation column;
• a reboiler associated with the distillation column that a) receives a portion of the NGL stream from the distillation column, b) heats the portion of the NGL stream to form a heated NGL stream, and c) returns the heated portion of the NGL stream to the distillation column;
• a compressor that compresses the residue gas stream to produce a hot and compressed residue gas stream;
• and
• a heat exchange apparatus that directs heat from the hot and compressed residue gas stream to the reboiler to provide heat to the reboiler to accomplish the function (b) of heating the portion of the NGL stream.