Abstract: A process for producing an ethylene copolymer, the process including: (a) contacting ethylene with at least one polar comonomer in the presence of at least one modifier and at least one free radical initiator in a tubular reactor under polymerization conditions including a pressure of from 225 to 270 MPa; (b) injecting the at least one free radical initiator into the reactor at a plurality of reaction zones spaced along the length of the reactor, wherein each reaction zone comprises an inlet and an outlet; (c) maintaining the temperature at the inlet of each reaction zone at 150° C. or less, and the temperature at the outlet of each reaction zone is at least 177° C.; (d) controlling the modifier flow at a rate of from 0.02 to 0.986 wt % of the copolymer; and (e) recovering the ethylene copolymer from the tubular reactor, is provided.

Abstract: This disclosure relates to systems and processes for cooling polymer product mixtures manufactured at high pressure. The processes of the invention involve cooling and then subsequently reducing the pressure of the product mixture from the reactor. In the systems of the invention, a product cooler is located downstream of the high pressure reactor and upstream of a high pressure let down valve.

Abstract: Controlling the shutdown of a polyethylene reactor system that includes a secondary compressor, a reactor, a high pressure let down valve (HPLDV), a high-pressure separator, and a high-pressure recycle gas system is provided. After a partial or complete shutdown of secondary compressor, HPLDV opens to a pre-set open position until the reactor pressure reduces to either a pre-set reduced pressure limit or a until the slope of the reactor gas density to reactor pressure exceeds 0.15. The HPLDV controls the pressure to a pressure set point.

Abstract: A process for producing ethylene polymer including compressing ethylene monomer in one or more compressors to a pressure from 1000 bar to 3000 bar; introducing the compressed ethylene monomer into one or more reactors; introducing a blend comprising an initiator and a modifier into the reactor where the ethylene monomer polymerizes forming a reaction mixture comprising unreacted ethylene monomer and ethylene polymer; and separating the ethylene polymer from the reaction mixture.

Abstract: 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.

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

Abstract: This disclosure relates to systems and processes for cooling polymer product mixtures manufactured at high pressure. The processes of the invention involve cooling and then subsequently reducing the pressure of the product mixture from the reactor. In the systems of the invention, a product cooler is located downstream of the high pressure reactor and upstream of a high pressure let down valve.

Abstract: This disclosure relates to systems and processes for cooling polymer product mixtures manufactured at high pressure. The processes of the invention involve cooling and then subsequently reducing the pressure of the product mixture from the reactor. In the systems of the invention, a product cooler is located downstream of the high pressure reactor and upstream of a high pressure let down valve.

Abstract: A process for producing an ethylene copolymer, the process including: (a) contacting ethylene with at least one polar comonomer in the presence of at least one modifier and at least one free radical initiator in a tubular reactor under polymerization conditions including a pressure of from 225 to 270 MPa; (b) injecting the at least one free radical initiator into the reactor at a plurality of reaction zones spaced along the length of the reactor, wherein each reaction zone comprises an inlet and an outlet; (c) maintaining the temperature at the inlet of each reaction zone at 150° C. or less, and the temperature at the outlet of each reaction zone is at least 177° C.; (d) controlling the modifier flow at a rate of from 0.02 to 0.986 wt % of the copolymer; and (e) recovering the ethylene copolymer from the tubular reactor, is provided.

Abstract: 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.

Abstract: 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.

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

Abstract: A process for separating components of a reactor off gas is provided. A related reactor system is also provided. The reactor system may include a high pressure tubular reactor and/or an autoclave reactor and may be used for the production polyolefin polymers.

Abstract: This disclosure relates to systems and processes for cooling polymer product mixtures manufactured at high pressure. The processes of the invention involve cooling and then subsequently reducing the pressure of the product mixture from the reactor. In the systems of the invention, a product cooler is located downstream of the high pressure reactor and upstream of a high pressure let down valve.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A process for separating components of a reactor off gas is provided. A related reactor system is also provided. The reactor system may include a high pressure tubular reactor and/or an autoclave reactor and may be used for the production polyolefin polymers.

Abstract: 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.

Abstract: A process for producing ethylene polymer including compressing ethylene monomer in one or more compressors to a pressure from 1000 bar to 3000 bar; introducing the compressed ethylene monomer into one or more reactors; introducing a blend comprising an initiator and a modifier into the reactor where the ethylene monomer polymerizes forming a reaction mixture comprising unreacted ethylene monomer and ethylene polymer; and separating the ethylene polymer from the reaction mixture.