The present invention relates to a process for reducing low molecular weight oligomers and wax build-up in one or more recycle coolers in a high pressure polymerization process by means of a gas stream, which is heated and/or free of wax, introduced into the one or more recycle coolers and the use of a heated gas stream for removing low molecular weight oligomers and wax build-up in one or more recycle coolers in a high pressure polymerization process.

The present invention relates to a process for reducing low molecular weight oligomers and wax build-up in one or more recycle coolers in a high pressure polymerization process by means of a gas stream, which is heated and/or free of wax, introduced into the one or more recycle coolers and the use of a heated gas stream for removing low molecular weight oligomers and wax build-up in one or more recycle coolers in a high pressure polymerization process.

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.

The present invention relates to a process for producing alpha-olefin polymers in a multistage polymerization process which includes at least two gas phase polymerization reactors, wherein unreacted gas withdrawn from the second gas phase polymerization reactor is compressed in a compressor and said compressed gas is fed via a conveying gas line into an outlet between a first outlet vessel downstream of the first gas phase polymerization reactor and said second gas phase polymerisation reactor. Such a process can alleviate problems of malfunction, disturbances or plugging of the transfer lines and enables higher productivity and considerable saving of energy and equipment cost. Moreover, the production of alpha-olefin polymers with varying and tailored properties is possible.

The present invention relates to a process for producing alpha-olefin polymers in a multistage polymerization process which includes at least two gas phase polymerization reactors, wherein unreacted gas withdrawn from the second gas phase polymerization reactor is compressed in a compressor and said compressed gas is fed via a conveying gas line into an outlet between a first outlet vessel downstream of the first gas phase polymerization reactor and said second gas phase polymerisation reactor. Such a process can alleviate problems of malfunction, disturbances or plugging of the transfer lines and enables higher productivity and considerable saving of energy and equipment cost. Moreover, the production of alpha-olefin polymers with varying and tailored properties is possible.

The present invention relates to an additive composition for controlling and inhibiting polymerization of monomers, wherein the composition comprises a combination of (a) a phenol compound comprising catechol compound with (b1) an aliphatic tertiary amine, (b2) oxide treated derivative of the aliphatic tertiary amine, or (b2) a mixture thereof, wherein the aliphatic tertiary amine contains one or more hydroxyl groups in the alkyl chain of the aliphatic tertiary amine. In one embodiment, the present invention also relates to a method for controlling and inhibiting polymerization of monomers by employing the additive composition of the present invention. In another embodiment, the present invention also relates to a method of using the additive composition of the present invention for controlling and inhibiting polymerization of monomers. In another embodiment, the present invention also relates to methods for controlling and inhibiting polymerization of monomers in a primary fractionator (or an ethylene plant), and for operating a primary fractionator, and for reducing fouling and polymer deposits in a primary fractionator, and to extend a run-length of a primary fractionator or of an ethylene plant.

Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

A method of forming polymerization auxiliaries for a polymerization process may include combining an antifouling agent with a killer agent to form an auxiliary composition; and contacting the auxiliary composition with an alkylaluminum. An antifouling complex may be produced by combining an antifouling agent with a killer agent to form an auxiliary composition; and contacting the auxiliary composition with an alkylaluminum.

A method of forming polymerization auxiliaries for a polymerization process may include combining an antifouling agent with a killer agent to form an auxiliary composition; and contacting the auxiliary composition with an alkylaluminum. An antifouling complex may be produced by combining an antifouling agent with a killer agent to form an auxiliary composition; and contacting the auxiliary composition with an alkylaluminum.