Process and apparatus for manufacturing ethylene polymers and copolymers

An apparatus for the manufacture of polyethylene and polyethylene copolymers comprising a primary compressor capable of a throughput of at least 55 tonnes/hr arranged to supply compressed ethylene to a two-stage secondary compressor and capable of compressing ethylene at a throughput of at least 120 tonnes/hr at a pressure of at least 2300 bar, the secondary compressor communicating, via a conduit provided with heating means to enable at least a portion of the compressed ethylene to be heated to at least 95° C., with the front end of a tubular reactor,

• the secondary compressor optionally communicating via one or more further conduits with one or more points downstream of the front end of the tubular reactor for the supply of one or more ethylene sidestreams to the tubular reactor,
• the tubular reactor having at least three inlets for the injection of initiator thereby defining at least three reaction zones and being provided with a heating/cooling jacket in each reaction zone, the tubular reactor having a maximum internal diameter of at least 65 mm and being provided with a high-pressure, let-down valve, the apparatus further comprising,
• a cooling means arranged downstream of the high-pressure, let-down valve,
• a product separator, and
• at least one conduit for the transfer of recycled ethylene from the product separator to the secondary compressor.