Abstract: A method for monitoring polymerization processes can include reacting by polymerization a feedstock in the presence of a catalyst in a reactor to produce an effluent comprising a polymer and a solvent; measuring a density of the effluent; and calculating a monomer conversion rate and/or a polymerization rate for the polymerization based on the density of the effluent. A system for monitoring polymerization processes can include a reactor containing an effluent comprising a solvent, a polymer, and a monomer; a flash vessel fluidly coupled to the reactor to receive the effluent from the reactor; and an inline density meter fluidly coupled to the reactor, placed between the reactor and the flash vessel, and configured to measure a density of the effluent.

Abstract: This disclosure describes polymerization processes and processes for quenching polymerization reactions using reactive particulates, such as amorphous silica, as quenching agents, typically in solution or bulk polymerization processes.

Abstract: Systems and methods are provided for conversion of polymers (such as plastic waste) to olefins. The systems and methods can include an initial pyrolysis stage where a plastic feedstock is delivered to the initial pyrolysis stage by one or more melt extruders. The one or more melt extruders can be heated to maintain the plastic feedstock in a liquid state during delivery of the plastic feedstock to the initial pyrolysis stage. This can allow for delivery of the plastic feedstock into the pyrolysis process with a controlled distribution of plastic into the pyrolysis reactor.

Abstract: A method for producing block copolymers can include polymerizing a feedstock comprising a monomer and a comonomer under first polymerization conditions in the presence of a catalyst in a reactor to produce a first effluent comprising a first polyolefin block, an unreacted monomer, and an unreacted comonomer; blending the first effluent with a coordinative chain transfer polymerization agent to produce a mixture; and polymerizing the mixture in a separator under second polymerization conditions to cause the unreacted monomer and the unreacted comonomer to polymerize onto one end of the first polyolefin block as a second polyolefin block, thereby forming a block copolymer, wherein the first polyolefin block has a first comonomer content and the second polyolefin block has a second comonomer content that is different than the first comonomer content. The method can further include polymerizing in presence of a second coordinative chain transfer polymerization agent in a second separator.

Abstract: A method for producing a polyolefin with a wide molecular weight distribution can comprise: polymerizing one or more monomers in the presence of a catalyst system in a loop reactor to produce a polyolefin product having a polydispersity index of 2.5 to 8, wherein the loop reactor comprises two or more reactors in series, and wherein the loop reactor has a loop thermal gradient of 50° C. to 150° C. and/or a standard deviation of inter-component thermal gradients along the loop reactor of 10° C. to 50° C.

Abstract: A process for the synthesis of a granular polymer, the process comprising (a) providing an active polymerization mixture that includes polymer, monomer, catalyst and optional solvent; (b) introducing a hydroxy-containing diaryl acetyl compound to the active polymerization mixture to thereby provide an inactive polymer mixture; (c) separating the polymer solution into a first stream and a second stream, where the first stream includes the polymer and the hydroxy-containing diaryl acetyl compound, and the second stream includes the monomer and the optional solvent; and (d) fabricating granules from the first stream.

Abstract: Process for feeding plastic material, e.g. a plastic waste, to a processor such as a thermochemical reactor, e.g. a pyrolysis reactor. The process comprises an optional shredder or disintegrator (1), a conveying system (2), a feed hopper (3) with a lock hopper or rotary valve, a melting tank (6) with an agitator (5) followed by a melt pump (7) for the delivery of molten plastic to the processor. The advantage of the current process includes the ability to supply a consistent, metered flow to the processor, independent of the recycled plastic's melt properties, or the form or particle size and distribution of the plastic material.

Abstract: A method for producing gradient copolymers can include polymerizing a reaction mixture comprising a monomer and a comonomer in the presence of a metallocene catalyst in a loop reactor, wherein in the loop reactor a gradient monomer weight percent in the reaction mixture is about 3 wt % to about 50 wt %, thereby forming a gradient copolymer.

Abstract: A method broadening a molecular weight distribution and/or broadening a chemical composition distribution of the polyolefin product can include: polymerizing a feedstock in the presence of a metallocene catalyst in a loop reactor to produce a polyolefin product, the feedstock comprising two or more monomers; and adjusting a polymerization parameter selected from the group consisting of decreasing a recycle ratio, increasing a polymer concentration, increasing a LRSU number, and any combination thereof.

Abstract: A method for determining polymer concentration can include synthesizing a polymer in a reactor under a set of parameters, wherein the reactor comprises a solution mixture having a refractive index, and wherein the solution mixture comprises a solvent, a polymer, and optionally a monomer, wherein the solution mixture has a polymer concentration; measuring the refractive index of the solution mixture; comparing the refractive index of the solution mixture with a calibration curve; and identifying the polymer concentration in the solution mixture. A system for determining polymer concentration can include a reactor containing a solution mixture comprising a solvent, a polymer, and optionally a monomer; a flash vessel fluidly coupled to the reactor to receive the solution mixture from the reactor; and a first refractometer fluidly coupled to the reactor, placed between the reactor and the flash vessel, and configured to measure a refractive index of the solution mixture.

Abstract: This invention relates to a polymerization process for forming polymer comprising: contacting (typically in a solution or slurry phase), a monomer and a catalyst system in a reaction zone comprising at least one spiral heat exchanger and recovering polymer, wherein the monomer, the catalyst system and the polymer flow through the at least one spiral heat exchanger in a cross-flow direction relative to spirals of the at least one spiral heat exchanger.

Abstract: This invention relates to a polymerization process for forming polymer comprising: contacting (typically in a solution or slurry phase), a monomer and a catalyst system in a reaction zone comprising at least one spiral heat exchanger and recovering polymer, wherein the monomer, the catalyst system and the polymer flow through the at least one spiral heat exchanger in a cross-flow direction relative to spirals of the at least one spiral heat exchanger.

Abstract: A method for washing an oligomerization reactor using by-product solvent recovered from the reactor can include: catalytically converting a monomer in a reactor section in a reaction mode in the presence of a catalyst to form a product stream comprising an oligomer, a by-product solvent, and a polymeric by-product; separating the product stream into a first fraction comprising the oligomer and a second fraction comprising a mixture of the by-product solvent and the polymeric by-product; and separating, in a thin film evaporator, the second fraction into a third fraction comprising the by-product solvent and a fourth fraction comprising the polymeric by-product.

Abstract: Methods and systems for solution polymerization. The method can include forming a first mixture stream consisting essentially of at least one catalyst and a process solvent, and forming a second mixture stream consisting essentially of at least one activator and the process solvent. The first mixture stream and the second mixture stream can be fed separately to at least one reaction zone comprising one or more monomers dissolved in the process solvent where the at least one monomers can be polymerized within the at least one reaction zone in the presence of the catalyst, activator and process solvent to produce a polymer product.

Abstract: This disclosure describes polymerization processes and processes for quenching polymerization reactions using reactive particulates, such as lecithin, as quenching agents, typically in solution or bulk polymerization processes.

Abstract: Disclosed is a solution polymerization process, or, alternatively, a method of delivering powder catalysts to a solution polymerization reactor, comprising combining a homogeneous single-site catalyst precursor with ?-olefin monomers to form a polyolefin, wherein the homogeneous single-site catalyst precursor is in the form of (i) a dry powder, (ii) suspended in a aliphatic hydrocarbon solvent, or (iii) suspended in an oil or wax, wherein the homogeneous single-site catalyst precursor is at a concentration greater than 0.8 mmole/liter when suspended in the aliphatic hydrocarbon solvent prior to entering the solution polymerization reactor.

Abstract: This disclosure describes polymerization processes and processes for quenching polymerization reactions using reactive particulates, such as amorphous silica, as quenching agents, typically in solution or bulk polymerization processes.

Abstract: This disclosure describes polymerization processes and processes for quenching polymerization reactions using reactive particulates, such as amorphous silica, as quenching agents, typically in solution or bulk polymerization processes.

Abstract: The present disclosure provides methods for the production of polymer blends using multiple reactors arranged in parallel. The methods comprise: providing a first feed comprising propylene to a first reactor operated in parallel with a second reactor; catalytically converting the first feed in the first reactor under polymer formation conditions utilizing a first catalyst to form a first product mixture; separating the first product mixture into a first fraction comprising polypropylene and a second fraction comprising unreacted propylene; providing a second feed comprising one or more elastomeric monomers to the second reactor; catalytically converting the second feed in the second reactor under polymer formation conditions utilizing a second catalyst different from the first catalyst to form a second product mixture comprising an elastomeric polymer; and blending the first fraction with the second product mixture downstream from the first reactor and the second reactor to form a polymer blend.

Abstract: A method for producing gradient copolymers can include polymerizing a reaction mixture comprising a monomer and a comonomer in the presence of a metallocene catalyst in a loop reactor, wherein in the loop reactor a gradient monomer weight percent in the reaction mixture is about 3 wt % to about 50 wt %, thereby forming a gradient copolymer.