Abstract: Disclosed are embodiments of a method of regenerating a desiccant in an off-line treater of a polyolefin production process. The method may include a heating phase followed by a cooling phase. The heating phase may involve use of a regenerating gas made from heating a treated a recycle stream of the polyolefin production process to regenerate desiccant in an off-line treater. The cooling phase may involve thermosyphoning the regenerating gas, nitrogen, an olefin-free diluent, or combinations thereof in a closed-convection loop of the off-line treater.

Abstract: A process includes hydrogenating, in a reaction zone, a highly unsaturated hydrocarbon received from a hydrocarbon stream to yield a product having an unsaturated hydrocarbon, the hydrogenating step occurring in the presence of a hydrogenation catalyst which has a selectivity for conversion of the highly unsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol % or greater based on the moles of the highly unsaturated hydrocarbon which are converted to the product, the hydrogenating step occurring in a reaction zone under conditions which include a flow index (IF) in a range of about 0.09 to about 35, wherein the IF is defined as: I F = F × [ CO ] V , wherein F is the flow rate of the hydrocarbon stream into the reaction zone in units of kg/h, [CO] is the concentration of carbon monoxide in the hydrocarbon stream in units of mol %, and V is the volume of the reaction zone in units of ft3.

Abstract: A system and method for startup of a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. In some embodiments, during startup the second reactor temperature control path is configured to allow the temperature of a second reactor to rise due to the heat of the exothermic polymerization reaction occurring within reactor until reaching a predetermined setpoint temperature. In other embodiments, during startup a first reactor temperature control path is configured to include a heat exchanger used as a cooler, and a second reactor temperature control path is configured to include a heat exchanger used as a heater, to raise the temperature of the second reactor until reaching a predetermined setpoint temperature.

Abstract: A system and method for startup of a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. In some embodiments, during startup the second reactor temperature control path is configured to allow the temperature of a second reactor to rise due to the heat of the exothermic polymerization reaction occurring within reactor until reaching a predetermined setpoint temperature. In other embodiments, during startup a first reactor temperature control path is configured to include a heat exchanger used as a cooler, and a second reactor temperature control path is configured to include a heat exchanger used as a heater, to raise the temperature of the second reactor until reaching a predetermined setpoint temperature.

Abstract: A process includes hydrogenating, in a reaction zone, a highly unsaturated hydrocarbon received from a hydrocarbon stream to yield a product having an unsaturated hydrocarbon, the hydrogenating step occurring in the presence of a hydrogenation catalyst which has a selectivity for conversion of the highly unsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol % or greater based on the moles of the highly unsaturated hydrocarbon which are converted to the product, the hydrogenating step occurring in a reaction zone under conditions which include a flow index (IF) in a range of about 0.09 to about 35, wherein the IF is defined as: I F = F × [ CO ] V , wherein F is the flow rate of the hydrocarbon stream into the reaction zone in units of kg/h, [CO] is the concentration of carbon monoxide in the hydrocarbon stream in units of mol %, and V is the volume of the reaction zone in units of ft3.

Abstract: Disclosed are embodiments of a method of regenerating a desiccant in an off-line treater of a polyolefin production process. The method may include a heating phase followed by a cooling phase. The heating phase may involve use of a regenerating gas made from heating a treated a recycle stream of the polyolefin production process to regenerate desiccant in an off-line treater. The cooling phase may involve thermosyphoning the regenerating gas, nitrogen, an olefin-free diluent, or combinations thereof in a closed-convection loop of the off-line treater.

Abstract: A system and method for startup of a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. In some embodiments, during startup the second reactor temperature control path is configured to allow the temperature of a second reactor to rise due to the heat of the exothermic polymerization reaction occurring within reactor until reaching a predetermined setpoint temperature. In other embodiments, during startup a first reactor temperature control path is configured to include a heat exchanger used as a cooler, and a second reactor temperature control path is configured to include a heat exchanger used as a heater, to raise the temperature of the second reactor until reaching a predetermined setpoint temperature.

Abstract: A system and method for a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. The shared temperature control path is configured to combine and process coolant return streams, and to provide coolant supply for the first reactor temperature control path and the second reactor temperature control path.

Abstract: A process includes hydrogenating, in a reaction zone, a highly unsaturated hydrocarbon received from a hydrocarbon stream to yield a product having an unsaturated hydrocarbon, the hydrogenating step occurring in the presence of a hydrogenation catalyst which has a selectivity for conversion of the highly unsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol % or greater based on the moles of the highly unsaturated hydrocarbon which are converted to the product, the hydrogenating step occurring in a reaction zone under conditions which include a flow index (IF) in a range of about 0.09 to about 35, wherein the IF is defined as: I F = F × [ CO ] V , wherein F is the flow rate of the hydrocarbon stream into the reaction zone in units of kg/h, [CO] is the concentration of carbon monoxide in the hydrocarbon stream in units of mol %, and V is the volume of the reaction zone in units of ft3.

Abstract: A system and method for a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. The shared temperature control path is configured to combine and process coolant return streams, and to provide coolant supply for the first reactor temperature control path and the second reactor temperature control path.

Abstract: A system and method for discharging a transfer slurry from a first polymerization reactor through a transfer line to a second polymerization reactor, the transfer slurry including at least diluent and a first polyethylene. A product slurry is discharged from the second polymerization reactor, the product slurry including at least diluent, the first polyethylene, and a second polyethylene. The velocity, pressure drop, or pressure loss due to friction in the transfer line is determined, and a process variable adjusted in response to the velocity, pressure drop, or pressure loss not satisfying a specified value.

Abstract: A system and method for polymerizing olefin in the presence of a chain transfer agent in a first reactor to form a first polyolefin, discharging from the first reactor a transfer slurry having the first polyolefin and the chain transfer agent, and processing the transfer slurry in a separator to remove chain transfer agent and to provide a fluff slurry having the first polyolefin and a lower content of chain transfer agent than in the transfer slurry. The system and method provide for feeding the fluff slurry to a second reactor, polymerizing olefin in the second reactor to form a second polyolefin, and discharging from the second reactor a slurry having the second polyolefin.

Abstract: A system and method for discharging a transfer slurry from a first polymerization reactor through a transfer line to a second polymerization reactor, the transfer slurry including at least diluent and a first polyethylene. A product slurry is discharged from the second polymerization reactor, the product slurry including at least diluent, the first polyethylene, and a second polyethylene. The velocity, pressure drop, or pressure loss due to friction in the transfer line is determined, and a process variable adjusted in response to the velocity, pressure drop, or pressure loss not satisfying a specified value.

Abstract: A system and method for discharging a transfer slurry from a first polymerization reactor through a transfer line to a second polymerization reactor, the transfer slurry including at least diluent and a first polyethylene. A product slurry is discharged from the second polymerization reactor, the product slurry including at least diluent, the first polyethylene, and a second polyethylene. The velocity, pressure drop, or pressure loss due to friction in the transfer line is determined, and a process variable adjusted in response to the velocity, pressure drop, or pressure loss not satisfying a specified value.

Abstract: A polyolefin production system including: a first reactor configured to produce a first discharge slurry having a first polyolefin; a second reactor configured to produce a second discharge slurry having a second polyolefin; and a post-reactor treatment zone having at least a separation vessel configured to receive the second discharge slurry or both the first discharge slurry and the second discharge slurry.

Abstract: A process comprising hydrogenating a highly unsaturated hydrocarbon in the presence of a first hydrogenation catalyst and a second hydrogenation catalyst to one or more compounds including an unsaturated hydrocarbon such that a total conversion of the highly unsaturated hydrocarbon is about 99 mol % or greater. In the process, the first hydrogenation catalyst, the second hydrogenation catalyst, or both, have a hydrogenation selectivity to the unsaturated hydrocarbon of about 90% or greater.

Abstract: A system and method for polymerizing olefin in the presence of a chain transfer agent in a first reactor to form a first polyolefin, discharging from the first reactor a transfer slurry having the first polyolefin and the chain transfer agent, and processing the transfer slurry in a separator to remove chain transfer agent and to provide a fluff slurry having the first polyolefin and a lower content of chain transfer agent than in the transfer slurry. The system and method provide for feeding the fluff slurry to a second reactor, polymerizing olefin in the second reactor to form a second polyolefin, and discharging from the second reactor a slurry having the second polyolefin.

Abstract: A system and method for a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. The shared temperature control path is configured to combine and process coolant return streams, and to provide coolant supply for the first reactor temperature control path and the second reactor temperature control path.

Abstract: The disclosure includes a polymerization process and an olefin polymerization system. A polymerization product is produced, a vapor phase is recovered from the polymerization product, the vapor phase is fractionated in a first column to yield a fraction stream, and the fraction stream is fractionated in a second column. A first stream of the second column, which comprises a diluent, can be recycled to a first polymerization reactor. A second stream of the second column, which comprises olefin monomer, diluent, and hydrogen, can be recycled to a second polymerization reactor. Comonomer may be recycled from the first column to the first polymerization reactor, the second polymerization reactor, or both.

Abstract: A technique for polymerizing ethylene on catalyst in a first polymerization reactor and in a second polymerization reactor to form polyethylene particles, and controlling particle size of the polyethylene particles.