Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

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.

Disclosed are systems and processes for distributing reactor coolant flow to the cooling jackets of a loop slurry reactor, where the reactor coolant is used to control the temperature of the loop slurry reactor in olefin polymerization. Also disclosed are systems and processes for controlling the temperature of the reactor coolant that is used for cooling olefin polymerization reactors, which can be used in combination with traditional coolant distribution regimes and in combination with the coolant distribution systems and processes that are disclosed herein.

A process of polymerizing olefins comprising combining propylene with a polymerization catalyst, hydrogen, and at least one external electron donor, such as at least one amino-silane donor, to form polypropylene in a first polymerization medium under solution or slurry conditions at or below the bubble point; removing hydrogen from the first polymerization medium and providing a first olefin/polyolefin separation step to form a second polymerization medium; transferring the second polymerization medium to a gas phase reactor and further combining with ethylene; obtaining a propylene-based impact copolymer. The propylene-based impact copolymer desirably has a melt flow rate of at least 60 g/10 min and is useful in automotive components.

A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

The invention relates to a process for the preparation of a composition comprising polylactide and lactide by ring-opening polymerization of lactide, said process comprising the steps of: (a) providing lactide and polymerization catalyst to a reactor, (b) melt polymerizing said lactide to a degree of polymerization of at most 96.0%, to form a composition comprising polylactide and lactide, and (c) removing said composition from the reactor, wherein the whole process is performed at pressures of at least 1 bar, and wherein the composition removed from the reactor is never subjected to a pressure below 1 bar and wherein the composition is not subjected to one of more devolatilization steps.

A reactor configuration is proposed for selectively converting gaseous, liquid or solid fuels to a syngas specification which is flexible in terms of H.sub.2/CO ratio. This reactor and system configuration can be used with a specific oxygen carrier to hydro-carbon fuel molar ratio, a specific range of operating temperatures and pressures, and a co-current downward moving bed system. The concept of a CO.sub.2 stream injected in-conjunction with the specified operating parameters for a moving bed reducer is claimed, wherein the injection location in the reactor system is flexible for both steam and CO.sub.2 such that, carbon efficiency of the system is maximized.

A method of producing bimodal ethylene-based polymer includes reacting ethylene monomer and C.sub.3-C.sub.12 α-olefin comonomer in the presence of a first catalyst in an agitated reactor to produce a first polymer fraction, and outputting effluent from the agitated reactor. A second catalyst is added to the effluent downstream of the agitated reactor and upstream from a non-agitated reactor, the second catalyst facilitates production of a second polymer fraction having a density and melt index (I.sub.2) different from the first polymer fraction. The second catalyst and effluent are mixed in at least one mixer. The second catalyst, second polymer fraction, and the first polymer fraction are passed to the non-agitated reactor; and additional ethylene monomer, additional C.sub.3-C.sub.12 α-olefin comonomer, and solvent are passed to the non-agitated reactor to produce more second polymer fraction and thereby the bimodal ethylene-based polymer.

The deterioration of methanol synthesis catalysts that is caused by iron poisoning of the catalyst is counteracted by using a catalyst containing a maximum of 100 ppmw Fe in the synthesis process. The method is especially useful in a methanol synthesis plant comprising a make-up gas compressor and a synthesis reactor in a methanol loop with a once-through pre-converter installed between the make-up gas compressor and the methanol loop.

The present disclosure relates generally to a system having a reactor system with a polymerization reactor and a feed system fluidly coupled to a feed inlet of the reactor. The feed system supplies components to the reactor via the feed inlet, and the reactor has a flow path that continuously conveys the components through the reactor and subjects the components to polymerization conditions to produce a polymer. The system also has an analysis system coupled to the reactor for online monitoring of a particle size of the polymer. Further, the system includes a control system, coupled to the analysis and feed systems, that receives a signal from the analysis system indicative of the monitored particle size of the polymer and adjusts an operating parameter of the feed system to control a flow rate of at least one of the components to the reactor based at least on the signal.