Techniques for converting a portion of a carbonate to hydroxide include receiving an alkaline carbonate solution that includes between 0.1M (moles per liter of solution) to 4.0M hydroxide and between 0.1M to 4.1M carbonate; reacting, in a slaking process, quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); and reacting the Ca(OH).sub.2 slurry and the alkaline carbonate solution to grow calcium carbonate (CaCO.sub.3) crystal aggregates of 0.0005 mm.sup.3 to 5 mm.sup.3 in volume in a fluidized-bed reactive crystallizer.

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.

A method of operating a polyethylene reactor system includes feeding ethylene, an optional first comonomer, a diluent, and a chromium-based catalyst to a first polymerization reactor. The method further includes contacting ethylene and the comonomer with the catalyst in the first polymerization reactor to form a first product including a first polyethylene. The method further includes feeding the first product from the first polymerization reactor to a second polymerization reactor. The method further includes contacting ethylene and a second optional comonomer with catalyst from the first reactor in the second polymerization reactor to form a second product including the first polyethylene and a second polyethylene. The method further includes controlling one or both of a molecular weight or a breadth of molecular weight distribution of the second product by adjusting a rate of hydrogen fed to one or both of the first polymerization reactor or the second polymerization reactor.

A method of operating a polyethylene reactor system includes feeding ethylene, an optional first comonomer, a diluent, and a chromium-based catalyst to a first polymerization reactor. The method further includes contacting ethylene and the comonomer with the catalyst in the first polymerization reactor to form a first product including a first polyethylene. The method further includes feeding the first product from the first polymerization reactor to a second polymerization reactor. The method further includes contacting ethylene and a second optional comonomer with catalyst from the first reactor in the second polymerization reactor to form a second product including the first polyethylene and a second polyethylene. The method further includes controlling one or both of a molecular weight or a breadth of molecular weight distribution of the second product by adjusting a rate of hydrogen fed to one or both of the first polymerization reactor or the second polymerization reactor.

This disclosure describes an improved heat transfer system for use in reaction vessels used in chemical and biological processes. In one embodiment, a heat transfer baffle comprising two sub-assemblies adjoined to one another is provided.

This disclosure describes an improved heat transfer system for use in reaction vessels used in chemical and biological processes. In one embodiment, a heat transfer baffle comprising two sub-assemblies adjoined to one another is provided.

The present disclosure relates to a process for manufacturing polyethylene. In the process, the purified liquid medium obtained from the wax-distilling process is further fed to a distillation column to obtain wet hexane comprising hexane fraction and moisture from the top of the column and heavies from the bottom of the column. The so obtained wet hexane is then treated in an adsorption unit to obtain dry hexane, which can be back-fed into the polymerization process. The process yields hexane with reduction in the concentration of the heavies, leading to reduction in the fouling of reactors and other equipments, thereby reducing the downtime of the reactors. The present disclosure also discloses an apparatus for manufacturing polyethylene. The apparatus has a simple and economic design and can be retrofitted in the existing plants.

The present disclosure relates to a process for manufacturing polyethylene. In the process, the purified liquid medium obtained from the wax-distilling process is further fed to a distillation column to obtain wet hexane comprising hexane fraction and moisture from the top of the column and heavies from the bottom of the column. The so obtained wet hexane is then treated in an adsorption unit to obtain dry hexane, which can be back-fed into the polymerization process. The process yields hexane with reduction in the concentration of the heavies, leading to reduction in the fouling of reactors and other equipments, thereby reducing the downtime of the reactors. The present disclosure also discloses an apparatus for manufacturing polyethylene. The apparatus has a simple and economic design and can be retrofitted in the existing plants.

A method for transforming selected renewable oils and fats, and optionally polyester waste plastic materials, into a plurality of reaction products via supercritical water is disclosed. The method comprises: conveying the selected oils and fats material through an extruder, wherein the extruder is configured to continuously convey the selected oils and fats material to a supercritical fluid reaction zone; injecting hot compressed water into the supercritical fluid reaction zone, while the extruder is conveying the selected oil and fats material into the supercritical fluid reaction zone so as to yield a mixture; retaining the mixture within the reaction zone for a period of time sufficient to yield the plurality of reaction products. The reaction zone may be characterized by a tubular reactor having an adjustably positionable inner tubular spear, wherein the tubular reactor and the inner tubular spear further define an annular space within the reaction zone, and wherein the mixture flows through the annular space and into a reaction products chamber.

A method for transforming selected renewable oils and fats, and optionally polyester waste plastic materials, into a plurality of reaction products via supercritical water is disclosed. The method comprises: conveying the selected oils and fats material through an extruder, wherein the extruder is configured to continuously convey the selected oils and fats material to a supercritical fluid reaction zone; injecting hot compressed water into the supercritical fluid reaction zone, while the extruder is conveying the selected oil and fats material into the supercritical fluid reaction zone so as to yield a mixture; retaining the mixture within the reaction zone for a period of time sufficient to yield the plurality of reaction products. The reaction zone may be characterized by a tubular reactor having an adjustably positionable inner tubular spear, wherein the tubular reactor and the inner tubular spear further define an annular space within the reaction zone, and wherein the mixture flows through the annular space and into a reaction products chamber.