Solution polymerization processes with reduced energy usage

An improved continuous solution polymerization process wherein energy consumption is reduced, comprising:

• i) injecting ethylene, one or more aliphatic hydrocarbon solvents, a first catalyst, optionally one or more α-olefins and optionally hydrogen into a first upstream reactor operating at a temperature and a pressure to produce an ethylene polymer in a single liquid phase solution;
• optionally, more than one upstream reactor may be employed, with the proviso that ethylene, one or more aliphatic hydrocarbon solvents, a second catalyst, optional one or more α-olefins and optional hydrogen are independently injected into said more than one upstream reactor to produce an ethylene polymer in a single liquid phase solution;
• wherein said first catalyst and said second catalyst may be the same or different;
• ii) injecting a catalyst deactivator, downstream of said first upstream reactor or optionally downstream of said more than one upstream reactor, into the single liquid phase solution containing ethylene, solvents, catalyst, ethylene polymer, optional α-olefins and optional hydrogen, to form a deactivated reactor solution;
• iii) passing the deactivated reactor solution through a heat exchanger to increase the temperature, followed by reducing the pressure, followed by producing a bottom stream of ethylene polymer rich solvents, deactivated catalyst and optional α-olefins and a gaseous overhead stream of ethylene, solvents, oligomers, optional α-olefins, and optional hydrogen in a V/L separator;
• iv) passing not more than 40% of the gaseous overhead stream to a distillation column;
• v) passing the remainder of the gaseous overhead stream through a halide removal column, followed by condensing the gaseous overhead stream by reducing the temperature while simultaneously generating a low pressure steam stream, to form a condensed overhead stream having a temperature from 145° C. to 180° C. and a pressure from 0.5 MPa to 5 MPa;
• vi) passing the condensed overhead stream through a means for oligomer removal, producing a cold recycle stream having a temperature from −25° C. to 60° C.;
• vii) passing the cold recycle stream through a lights separator to remove volatile components to produce a purged recycle stream;
• viii) passing the purged recycle stream through at least two purification vessels, producing a purified recycle stream;
• ix) collecting the purified recycle stream in a recycle drum, passing the purified recycle stream through pump and injecting a high pressure recycle stream into said first upstream reactors or optionally more than one upstream reactor;
• wherein said high pressure recycle stream has a pressure from 3 to 45 MPa, with the proviso that said high pressure recycle stream has a higher pressure than said first upstream reactor.