A process and system for maintaining optimum polymerization production in a loop polymerization reactor by continuously and periodically obtaining polymerization results, such as melt index (MI), production rate and ash content of the polymer produced, determining whether each of the results is within desired ranges, storing and averaging recently obtained results in a database within a reaction rate controller program, and when one of the results is out of the desired range modifying at least one reaction parameter set-point such as monomer concentration, catalyst feed rate and reactor temperature to drive any out-of-range polymerization result(s) toward the desired range for that result.

A process for maintaining an optimum polymerization process in a continuous loop polymerization reactor by driving a catalyst feed range set-point around a bad catalyst set-point range using a bad catalyst feed rate program to vary the catalyst feed rate for differing periods of time between previously determined good catalyst feed rates.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

Disclosed are a reaction tower, a production system, and a production method for producing potassium manganate. The reaction tower includes a reaction tower body and a bubble generator. The reaction tower body has a reaction chamber. The bubble generator includes an outer housing. The outer housing is disposed in the reaction chamber and has a gas flow channel therein. The outer housing is configured to direct an external reactant gas into the gas flow channel. The outer housing is provided with multiple first pores each having a diameter less than 10 mm, via which the gas flow channel communicates with the reaction chamber. The reaction tower is used in the production system. The reactant gas is introduced into the reaction chamber in the form of small bubbles by the action of the bubble generator, to increase the area of contact of the reactant gas with manganese ore powder and lye.

The present invention relates to multi reactor configurations for producing polypropylene copolymers and to processes for producing polypropylene copolymers. The reactor configuration for the production of propylene copolymers comprises at least three reactors R1, R1 and R3, all reactors having inlet and outlet, whereby reactors R2 and R3 are configured in parallel both downstream of reactor R1; and whereby reactor R1 is configured in series and upstream of reactors R2 and R3, and whereby the outlet of reactor R1 is coupled with the inlets of both reactors R2 and R3.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

The present invention is directed to a polypropylene composition (C) comprising an α-nucleated heterophasic composition (HECO) comprising a (semi)crystalline polypropylene (PP1), an elastomeric ethylene/propylene copolymer (EPR) and a first α-nucleating agent (NU1), an impact modifier comprising a polyethylene (PE) being a copolymer of ethylene and a C.sub.4-C.sub.12 α-olefin and a second α-nucleating agent (NU2). The present invention is further directed to a method for preparing said polypropylene composition (C) and an article comprising said polypropylene composition (C). The present invention is also directed to the use of a composition comprising a polyethylene (PE) being a copolymer of ethylene and a C.sub.4-C.sub.12 α-olefin and an α-nucleating agent (NU2) as an impact modifier.

A method is provided for producing at least one olefin by oxidative dehydrogenation of a hydrocarbon feed. The method includes the steps of contacting a hydrocarbon feed, which includes at least one alkane, and a steam feed with an oxygen transfer agent under a pressure of 1.1 bar to 800 bar to produce at least one olefin. The oxygen transfer agent contains a metal oxide that acts as an oxidizing agent to oxidize the at least one alkane. Additionally, the method includes the step of collecting a product stream containing the at least one olefin.

Disclosed are a reaction tower, a production system, and a production method for producing potassium manganate. The reaction tower includes a reaction tower body and a bubble generator. The reaction tower body has a reaction chamber. The bubble generator includes an outer housing. The outer housing is disposed in the reaction chamber and has a gas flow channel therein. The outer housing is configured to direct an external reactant gas into the gas flow channel. The outer housing is provided with multiple first pores each having a diameter less than 10 mm, via which the gas flow channel communicates with the reaction chamber. The reaction tower is used in the production system. The reactant gas is introduced into the reaction chamber in the form of small bubbles by the action of the bubble generator, to increase the area of contact of the reactant gas with manganese ore powder and lye.

A method is provided for producing at least one olefin by oxidative dehydrogenation of a hydrocarbon feed. The method includes the steps of contacting a hydrocarbon feed, which includes at least one alkane, and a steam feed with an oxygen transfer agent under a pressure of 1.1 bar to 800 bar to produce at least one olefin. The oxygen transfer agent contains a metal oxide that acts as an oxidizing agent to oxidize the at least one alkane. Additionally, the method includes the step of collecting a product stream containing the at least one olefin.