Abstract: Both a system and method for cleaning a low pressure separation vessel of a high pressure polyethylene polymerization plant are provided. The system includes a polytetrafluoroethylene lining that covers the interior surfaces of the vessel, and a cover mounting assembly including an annular clamp for detachably mounting a cover over the vessel. The mounting assembly includes a clamp actuator for quickly securing and releasing the cover with respect to a top rim of the vessel. The vessel is drained of liquid polyethylene and allowed to cool to ambient temperature, thus creating a frozen “skin” of polyethylene around the interior surfaces of the vessel. The clamp actuator releases the cover. The polyethylene skin is peeled off the interior sides the vessel and gathered up at the top to form a neck, thus peeling the polyethylene skin away from the polytetrafluoroethylene lining along with any degraded polymers or other impurities that have accumulated on the interior surfaces of the vessel.

Abstract: Both a system and method for cleaning a low pressure separation vessel of a high pressure polyethylene polymerization plant are provided. The system includes a polytetrafluoroethylene lining that covers the interior surfaces of the vessel, and a cover mounting assembly including an annular clamp for detachably mounting a cover over the vessel. The mounting assembly includes a clamp actuator for quickly securing and releasing the cover with respect to a top rim of the vessel. The vessel is drained of liquid polyethylene and allowed to cool to ambient temperature, thus creating a frozen “skin” of polyethylene around the interior surfaces of the vessel. The clamp actuator releases the cover. The polyethylene skin is peeled off the interior sides the vessel and gathered up at the top to form a neck, thus peeling the polyethylene skin away from the polytetrafluoroethylene lining along with any degraded polymers or other impurities that have accumulated on the interior surfaces of the vessel.

Abstract: The invention relates to an apparatus for the high pressure polymerisation of ethylene which comprises a high pressure reactor; a conduit for the supply of ethylene to the reactor, the conduit being provided with a preheater for heating the ethylene; a waste heat boiler for the production of medium pressure steam; a source of high pressure steam; and a steam distribution system comprising a medium pressure steam net for the distribution of medium pressure steam from the waste heat boiler, in which the preheater comprises first, second and third sections and the steam distribution system is such that the first section can be supplied with steam from the medium pressure steam net, the second section can be supplied with steam from the medium pressure steam net or with high pressure steam and the third section can be supplied with high pressure steam.

Abstract: The invention relates to an apparatus for the high pressure polymerisation of ethylene which comprises a high pressure reactor; a conduit for the supply of ethylene to the reactor, the conduit being provided with a preheater for heating the ethylene; a waste heat boiler for the production of medium pressure steam; a source of high pressure steam; and a steam distribution system comprising a medium pressure steam net for the distribution of medium pressure steam from the waste heat boiler, in which the preheater comprises first, second and third sections and the steam distribution system is such that the first section can be supplied with steam from the medium pressure steam net, the second section can be supplied with steam from the medium pressure steam net or with high pressure steam and the third section can be supplied with high pressure steam.