A process to separate a multi-component hydrocarbon stream which includes ethylene, at least one polymer and other components, the process including: in a first flash stage, flashing the multi-component hydrocarbon stream, from an elevated pressure of more than 30 bar(a) and an elevated temperature in the range of 150°C to 185°C to a flash pressure in the range of 10 bar(a) to 30 bar(a), producing a first ethylene-containing vapour overheads product at a pressure in the range of 10 bar(a) to 30 bar(a) and a first flash stage bottoms product which includes some ethylene, said at least one polymer and some of said other components, the flash pressure and the elevated temperature of the multi-component hydrocarbon stream being selected such that the first flash stage bottoms product has a concentration of said at least one polymer of less than 5% by mass to render the viscosity of the first flash stage bottoms product at the temperature of the first flash stage bottoms product in the first flash stage at less than 1000 cP at a shear of 1 per second; heating at least a portion of the first flash stage bottoms product to a temperature in excess of 150°C to form a heated first flash stage bottoms product; combining a recycle portion of said heated first flash stage bottoms product with the multi-component hydrocarbon stream, which is at a temperature less than 150°C before combination with said recycle portion, thereby to heat the multi-component hydrocarbon stream to said elevated temperature in the range of 150°C to 185°C; withdrawing at least a portion of the first flash stage bottoms product which includes some ethylene, said at least one polymer and some of said other components, from the first flash stage; and removing the first ethylene-containing vapour overheads product from the first flash stage. in a first flash stage, flashing the multi-component hydrocarbon stream, from an elevated pressure of more than 30 bar(a) and an elevated temperature in the range of 150°C to 185°C to a flash pressure in the range of 10 bar(a) to 30 bar(a), producing a first ethylene-containing vapour overheads product at a pressure in the range of 10 bar(a) to 30 bar(a) and a first flash stage bottoms product which includes some ethylene, said at least one polymer and some of said other components, the flash pressure and the elevated temperature of the multi-component hydrocarbon stream being selected such that the first flash stage bottoms product has a concentration of said at least one polymer of less than 5% by mass to render the viscosity of the first flash stage bottoms product at the temperature of the first flash stage bottoms product in the first flash stage at less than 1000 cP at a shear of 1 per second; heating at least a portion of the first flash stage bottoms product to a temperature in excess of 150°C to form a heated first flash stage bottoms product; combining a recycle portion of said heated first flash stage bottoms product with the multi-component hydrocarbon stream, which is at a temperature less than 150°C before combination with said recycle portion, thereby to heat the multi-component hydrocarbon stream to said elevated temperature in the range of 150°C to 185°C; withdrawing at least a portion of the first flash stage bottoms product which includes some ethylene, said at least one polymer and some of said other components, from the first flash stage; and removing the first ethylene-containing vapour overheads product from the first flash stage.