Exxonmobil Chemical Patents Inc.

Philip H Cornelissen

Henri Aime Lammens

Paul Jan Clymans

Christopher Kim Morgan

Ivo T Goossens

Fausto F Ciancio

Jan J Naets

Tom Van Nuland

Leo E Reynders

Willy De Koster

Dirk H Brouns

Martin J Decoster

A process and system for cleaning a high pressure separator vessel in a polymerization reactor without removing the top cover and its associated bolts by providing a cleaning hole in a fluid fitting above and adjacent to the top cover, through which a cord or cable is fed and affixed to a rotatable cleaning nozzle. The cleaning nozzle is gradually raised, lowered and rotated to direct a high pressure liquid onto the interior walls of the vessel to remove accumulated waste material.

High pressure separator cleaning methods and apparatus

Systems and processes for rapidly depressurizing a reactor system are disclosed. The systems and processes are particularly useful in the high pressure polymerization of ethylene.

Rapid depressurization of a reactor system

Disclosed are an apparatus and a process for polymerizing ethylene under high pressure providing more than one injection point for one initiator injection pump.

Apparatus and process for high pressure polymerization of ethylene

A method and pressure relief assembly for relieving a condition of over-pressure in a vessel are provided. In addition, a separator vessel suitable for operation in a process for polymerizing one or more olefins is provided.

Methods of relieving a condition of over-pressure in a vessel, pressure relief assemblies, and related separator vessels

Systems and processes for controlling fouling in the manufacture of ethylene polymers and copolymers at high pressure. Disclosed is a high pressure polyethylene polymerization system comprising a reactor, a primary compressor, and a secondary compressor, the secondary compressor comprising: a) a first stage, wherein the first stage comprises at least two cylinders, and the discharge pipes of the at least two cylinders are fluidly connected by a first stage discharge cross-connect pipe; b) a second stage; c) an interstage; and d) a first cooler applied to the interstage piping starting at a location within 10 meters downstream of the first stage discharge cross-connect pipe.

Control of fouling in high pressure polyethylene manufacture

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.

Separation vessels for use in polymerization processes and methods for cleaning same

A system including a vessel with at least two fluid inlets and a fluid outlet wherein one fluid inlet is positioned higher in the vessel than the other fluid inlet is provided. The fluid inlets may be connected to a polymerization reactor and each fluid inlet may be configured to deliver fluid to the vessel from a different zone of the polymerization reactor. During shut-down of a polymerization reactor, reaction mixture is discharged to a separation system where polymer particles are removed from the mixture prior to being released into the atmosphere.

Fluid separation systems and methods

Embodiments of the invention provide an apparatus for the manufacture of polyethylene and polyethylene copolymers. The apparatus includes a primary compressor in fluid communication with a two-stage secondary compressor, the secondary compressor in fluid communication with a heated conduit in fluid communication with a tubular reactor, the tubular reactor including one or more reaction zones having a heating/cooling jacket, said reactor tube including an inner material and an outer material, said outer material being substantially inert in the presence of water under operating conditions, the tubular reactor in fluid communication with a product separator, and at least one conduit for the transfer of recycled ethylene from the product separator to the secondary compressor. Processes for manufacturing polyethylene and polyethylene copolymers using such an apparatus are also described.

Apparatus and process for making high-pressure polyethylene polymers and copolymers

The invention provides a process and an apparatus for the high pressure polymerization of ethylene in which a jet pump is used to pump a fluid into a polymer/monomer product mixture leaving a bumped tubular reactor. The fluid may be recycled monomer or another fluid such as a modifier.

Process for the production of polyethylene and ethylene copolymers

The invention relates to a process for the manufacture of ethylene polymers and copolymers in which ethylene is compressed in a primary compressor at a throughput of at least 55 tonnes/hour, mixed with recycled ethylene and further compressed in a two-stage reciprocating secondary compressor having at least 14 cylinders to a pressure of at least 2300 bar at a throughput of at least 120 tonnes/hour, heating at least a portion of that ethylene to a temperature of at least 95&#xb0; C. and introducing it into a tubular reactor of diameter at least 65 mm and a length of at least 1500 m, introducing initiator in at least three reaction zones to give a conversion of at least 28% and maintaining a pressure drop over the reactor to maintain a flow velocity of at least 6 m/s.

Process and apparatus for manufacturing ethylene polymers and copolymers

The invention provides a compressor for use as a secondary compressor for an ethylene polymerization tubular reactor comprising a motor and at least two compressor frames, at least one of the compressor frames being coupled to the motor by means of a contoured diaphragm flexible coupling.

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Heverlee, Belgium

Philip H Cornelissen