摘要:
In some embodiments, a method in which at least one continuity additive (“CA”) and a seed bed are pre-loaded into a reactor, and a polymerization reaction is optionally then performed in the reactor. In other embodiments, at least one flow improver, at least one CA, and a seed bed are pre-loaded into a reactor. Pre-loading of a reactor with a CA can significantly improve continuity of a subsequent polymerization reaction in the reactor during its initial stages, including by reducing sheeting and fouling. The CA can be pre-loaded in dry form (e.g., as a powder), or in liquid or slurry form (e.g., as an oil slurry). To aid delivery of a dry CA to the reactor and combination of the dry CA with a seed bed in the reactor, the dry CA can be combined with a flow improver and the combination of CA and flow improver then loaded into the reactor. Alternatively, the CA and flow improver can be sequentially loaded into the reactor, and then mixed together (and mixed with a seed bed) in the reactor after both the CA and flow improver have been separately loaded into the reactor.
摘要:
In some embodiments, a method in which at least one continuity additive (“CA”) and a seed bed are pre-loaded into a reactor, and a polymerization reaction is optionally then performed in the reactor. In other embodiments, at least one flow improver, at least one CA, and a seed bed are pre-loaded into a reactor. Pre-loading of a reactor with a CA can significantly improve continuity of a subsequent polymerization reaction in the reactor during its initial stages, including by reducing sheeting and fouling. The CA can be pre-loaded in dry form (e.g., as a powder), or in liquid or slurry form (e.g., as an oil slurry). To aid delivery of a dry CA to the reactor and combination of the dry CA with a seed bed in the reactor, the dry CA can be combined with a flow improver and the combination of CA and flow improver then loaded into the reactor. Alternatively, the CA and flow improver can be sequentially loaded into the reactor, and then mixed together (and mixed with a seed bed) in the reactor after both the CA and flow improver have been separately loaded into the reactor.
摘要:
A process for the production of an ethylene alpha-olefin copolymer is disclosed, the process including polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20° C. to 150° C. to form an ethylene alpha-olefin copolymer. The resulting ethylene alpha-olefin copolymer may have a density D of 0.927 g/cc or less, a melt index (I2) of from 0.1 to 100 dg/min, a MWD of from 1.5 to 5.0. The resulting ethylene alpha-olefin copolymer may also have a peak melting temperature Tmax second melt satisfying the following relation: Tmax second melt>D*398−245.
摘要:
Processes for the polymerization of olefins with extracted metal carboxylate salts are provided. The polymerization processes have increased productivity and/or increased resin bulk density.
摘要:
Disclosed is a method for using at least one static probe during polymerization in a fluid bed polymerization reactor system to monitor a coating on a surface of the reactor system and a distal portion of each static probe, wherein the coating is exposed to flowing fluid within the reactor system during the reaction. The surface may be a reactor bed wall (exposed to the reactor's fluid bed) and the coating is exposed to flowing, bubbling fluid within the fluid bed during the reaction. The method may include steps of: during the polymerization reaction, operating the static probe to generate a sequence of data values (“high speed data”) indicative of fluid flow variation (e.g., bubbling or turbulence), and determining from the high speed data at least one electrical property of the coating (e.g., of a portion of the coating on the distal portion of the static probe).
摘要:
A method for monitoring a polymer resin-producing polymerization reaction in a fluid bed reactor, including by determining in on-line fashion a maximum diluent (e.g., ICA) concentration and an optimal diluent (e.g., ICA) concentration in the reactor, whereby performing the reaction with diluent (e.g., ICA) concentration less than the maximum diluent concentration ensures an acceptably low risk that the resin in the reactor in the presence of condensable diluent gas will reach a condition of limiting stickiness. Preferably, the optimal diluent concentration maximizes production rate subject to relevant constraints. The method can also include at least one of the steps of controlling the reaction to achieve a desired production rate by controlling diluent (e.g., ICA) concentration, and controlling the reaction to prevent reactor temperature from reaching a reduced melt reference temperature at least substantially equal to a dry melt reference temperature minus a temperature depression value by which the dry melt reference temperature is depressed by presence of at least one condensable diluent gas with the resin in the reactor.
摘要:
This invention relates to a process for maintaining heat transfer capacity of a cycle cooler while polymerizing olefin(s) in the presence of catalyst and a carboxylate metal salt by controlling the amount of carboxylate metal salt present in the reaction system. In particular, the invention relates to maintaining a cycle cooler performance parameter substantially constant while polymerizing olefin(s) in the presence of a carboxylate metal salt and a conventional-type transition metal polymerization catalyst compound, or a metallocene-type polymerization catalyst compound. This invention further relates to a process wherein the cycle cooler performance parameter is a heat transfer capacity of the cycle cooler, a pressure drop across the cooler, or a cooler approach temperature of a cycle cooler.
摘要:
A method for monitoring a polymer resin-producing polymerization reaction in a fluid bed reactor, including by determining in on-line fashion a maximum diluent (e.g., ICA) concentration and an optimal diluent (e.g., ICA) concentration in the reactor, whereby performing the reaction with diluent (e.g., ICA) concentration less than the maximum diluent concentration ensures an acceptably low risk that the resin in the reactor in the presence of condensable diluent gas will reach a condition of limiting stickiness. Preferably, the optimal diluent concentration maximizes production rate subject to relevant constraints. The method can also include at least one of the steps of controlling the reaction to achieve a desired production rate by controlling diluent (e.g., ICA) concentration, and controlling the reaction to prevent reactor temperature from reaching a reduced melt reference temperature at least substantially equal to a dry melt reference temperature minus a temperature depression value by which the dry melt reference temperature is depressed by presence of at least one condensable diluent gas with the resin in the reactor.
摘要:
Branched ethylene-propylene compositions which have improved melt strength and shear thinning are provided. The weight average branching index g′ for the higher molecular weight region of the ethylene-propylene composition is less than 0.95. Additionally, a novel process is provided for efficiently producing a branched ethylene-propylene composition comprising: a) contacting propylene monomers and ethylene monomers in a reactor with an inert hydrocarbon solvent or diluent and a catalyst composition comprising one or more single site catalyst compounds capable of producing an ethylene-propylene polymer at a temperature from about 50° C. to about 180° C., wherein the ratio in the reactor of the propylene and ethylene monomers to the inert hydrocarbon solvent or diluent is less than 2.0, and further, wherein the propylene and ethylene monomers and the inert hydrocarbon solvent or diluent comprise no more than 90 percent of the total contents of the reactor; and b) recovering a branched ethylene-propylene composition, wherein the weight average branching index g′ for the higher molecular weight region of the ethylene-propylene composition is less than 0.95.
摘要:
A composition of matter comprising vinyl ended copolymer chains having a number average molecular weight (Mn) of about 1500 to 75,000, the number average molecular weight being determined by gel permeation chromatography (GPC) at 145° C., a ratio of vinyl groups to total olefin groups according to the formula vinyl groups olefin groups ≥ ( comonomer mole percent + 0.1 ) a × 10 a × b ( 1 ) where a and b have the following sets of valuer: when a=−0.24, b=0.8; when a=−0.20, b=0.8; when a=−0.18, b=0.83; when a=−0.15, b=0.83; and when a=−0.10, b=0.85; and where the total number of vinyl groups per 1000 carbon atoms is in the range from greater than 0.13 to less than 9.85, the vinyl group measurement being taken by GPC (145° C.) and 1H-NMR (125° C.).