NOVELTY - Recovering ethylene involves recovering an ethylene-containing stream comprises methane, ethylene, and nitrogen oxides from at least one of an ethylene production process and an ethylene recovery process; separating the ethylene-containing stream via extractive distillation using at least one greater than or equal to 2C hydrocarbon absorbent to produce an overheads fraction comprises methane and nitrogen oxides and a bottoms fraction comprises the greater than or equal to 2C hydrocarbon absorbent and ethylene.    USE - For recovering ethylene (claimed).    ADVANTAGE - The method recovers ethylene and heavier olefins from ethylene-containing streams by reduced capital, operating costs, and separation requirements for other non-olefin components present in ethylene-containing streams; is design to operating temperatures of - greater than or equal to 90 (preferably greater than or equal to one quarter 0) degrees C, thus eliminate the need for expensive methane refrigeration loops commonly used in cryogenic separation schemes; uses propane and propylene refrigeration that provides chilling for processes, thus reduces capital investment costs, operating costs, and improves reliability.    DETAILED DESCRIPTION - Recovering ethylene involves recovering an ethylene-containing stream comprises methane, ethylene, and nitrogen oxides from at least one of an ethylene production process and an ethylene recovery process; separating the ethylene-containing stream via extractive distillation using at least one greater than or equal to 2C hydrocarbon absorbent to produce an overheads fraction comprising methane and nitrogen oxides and a bottoms fraction comprises the greater than or equal to 2C hydrocarbon absorbent and ethylene; where the separating by operating the extractive distillation at temperatures and pressures sufficient to prevent any substantial conversion of nitrogen oxides to dinitrogen dioxide (N2O3). where the step of separating is by operating the extractive distillation at temperatures and pressures that are sufficient to prevent any substantial conversion of nitrogen oxides to dinitrogen dioxide (N2O3).