It is provided a process for producing an ethylene copolymer comprising compressing ethylene monomer at a certain pressure; adding a fresh comonomer in liquid form and, optionally, a fresh modifier in liquid form at a certain pressure to the compressed ethylene monomer; introducing the resulting compressed mixture into an autoclave reactor having a first reaction zone and at least one more reaction zone, the first reaction zone having a volume that is greater than 50% of the total reactor volume, and, optionally, at least one additional reactor; adding at least one free radical initiator in order to start a polymerization reaction; and separating the ethylene copolymer from the reaction mixture; wherein all the compressed ethylene monomer or the compressed mixture are introduced into the first reaction zone of the autoclave reactor, and wherein the compressed mixture is introduced into the autoclave reactor and, optionally, into the at least one additional reactor at a temperature from −20° C. to 70° C.

An apparatus for preparing polyalpha-olefins includes a mixing unit, a microchannel reaction unit, a high-pressure separation unit, a low-pressure separation unit, a gas circulation unit, a post-treatment unit and a pressure control unit, the mixing unit, the microchannel reaction unit, the high-pressure separation unit, the low-pressure separation unit that are successively connected. The gas circulation unit, the microchannel reaction unit is provided with the BF.sub.3 gas inlet, the mixing unit is provided with the auxiliary feed inlet, and the olefin raw material inlet, the gas circulation unit is connected with the BF.sub.3 gas inlet, the low-pressure separation unit is further connected with the post-treatment unit, and the high-pressure separation unit, the pressure control unit, and the gas circulation unit are further successively connected. The apparatus has the advantages of high polymerization reaction speed, high reaction conversion and good product selectivity, and is suitable for large-scale industrial production.

An apparatus for preparing polyalpha-olefins includes a mixing unit, a microchannel reaction unit, a high-pressure separation unit, a low-pressure separation unit, a gas circulation unit, a post-treatment unit and a pressure control unit, the mixing unit, the microchannel reaction unit, the high-pressure separation unit, the low-pressure separation unit that are successively connected. The gas circulation unit, the microchannel reaction unit is provided with the BF.sub.3 gas inlet, the mixing unit is provided with the auxiliary feed inlet, and the olefin raw material inlet, the gas circulation unit is connected with the BF.sub.3 gas inlet, the low-pressure separation unit is further connected with the post-treatment unit, and the high-pressure separation unit, the pressure control unit, and the gas circulation unit are further successively connected. The apparatus has the advantages of high polymerization reaction speed, high reaction conversion and good product selectivity, and is suitable for large-scale industrial production.

Methods of reducing heat exchanger fouling rate or of producing polyolefins may include providing a first gas stream comprising a gas and entrained fine polyolefin particles to a gas outlet line; removing a portion of the entrained fine polyolefin particles from the gas outlet line to form a bypass stream; and providing the bypass stream to a bypass line comprising a bypass line inlet and a bypass line outlet. The bypass line inlet and outlet are located upstream and downstream of a first heat exchanger. The methods may further include providing at least a portion of the first gas stream to the first heat exchanger; and combining the bypass stream and a second gas stream at the bypass line outlet to form a combined gas stream comprising one or more olefins or paraffins. A temperature of the combined gas stream is below the dew point of the combined gas stream.

Methods of reducing heat exchanger fouling rate or of producing polyolefins may include providing a first gas stream comprising a gas and entrained fine polyolefin particles to a gas outlet line; removing a portion of the entrained fine polyolefin particles from the gas outlet line to form a bypass stream; and providing the bypass stream to a bypass line comprising a bypass line inlet and a bypass line outlet. The bypass line inlet and outlet are located upstream and downstream of a first heat exchanger. The methods may further include providing at least a portion of the first gas stream to the first heat exchanger; and combining the bypass stream and a second gas stream at the bypass line outlet to form a combined gas stream comprising one or more olefins or paraffins. A temperature of the combined gas stream is below the dew point of the combined gas stream.

A high-pressure polymerization system having a) a polymerization reactor and b) a reactor blow down system having b1) a reactor blow down vessel, having a circular design over a major portion P having a L/D-ratio in the range from 1.75 to 10.0 and containing an aqueous quenching medium, b2) a release line connecting the polymerization reactor with the reactor blow down vessel and having an outlet located above a maximum level for the aqueous quenching medium, b3) a first emergency valve in the release line to open and close fluid communication between the polymerization reactor and the reactor blow down system, and wherein the release line outlet has a joining piece having an angle (a) between the central axis and a tangent at the reactor blow down vessel in the range from 5° to 70° and the reactor blow down vessel has a vent stack containing a constricted section.

A high-pressure polymerization system having a) a polymerization reactor and b) a reactor blow down system having b1) a reactor blow down vessel, having a circular design over a major portion P having a L/D-ratio in the range from 1.75 to 10.0 and containing an aqueous quenching medium, b2) a release line connecting the polymerization reactor with the reactor blow down vessel and having an outlet located above a maximum level for the aqueous quenching medium, b3) a first emergency valve in the release line to open and close fluid communication between the polymerization reactor and the reactor blow down system, and wherein the release line outlet has a joining piece having an angle (a) between the central axis and a tangent at the reactor blow down vessel in the range from 5° to 70° and the reactor blow down vessel has a vent stack containing a constricted section.

The present disclosure provides a composition. In an embodiment, the composition is an ethylene-based polymer composition formed by high pressure (greater or equal to 100 MPa) free radical polymerization. The ethylene-based polymer composition includes ethylene monomer and a mixture of hydroxyl-terminated polybutadiene molecules (PB-OH). Each PB-OH molecule includes internal alkene groups and terminal alkene groups. Each PB-OH molecule has more internal alkene groups than terminal alkene groups.

The present disclosure provides a composition. In an embodiment, the composition is an ethylene-based polymer composition formed by high pressure (greater or equal to 100 MPa) free radical polymerization. The ethylene-based polymer composition includes ethylene monomer and a mixture of hydroxyl-terminated polybutadiene molecules (PB-OH). Each PB-OH molecule includes internal alkene groups and terminal alkene groups. Each PB-OH molecule has more internal alkene groups than terminal alkene groups.

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.