Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide obtained by hydrolyzing acrylonitrile in water in the presence of a biocatalyst capable of converting acrylonitrile to acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide gel hold in a transportable polymerization unit from a location A to a location B. The aqueous polyacrylamide gel furthermore comprises at least one stabilizer for prevention of polymer degradation.

Abstract: Process of providing polyacrylamides to a site-of-use comprising at least the steps of mixing a polyacrylamide powder at a manufacturing site with an aqueous liquid, thereby obtaining a homogeneous aqueous polyacrylamide concentrate, transporting said concentrate in a transport unit from the manufacturing site to the site-of-use, and removing the homogeneous aqueous concentrate from the transport unit at the site-of-use. Process of treating subterranean, oil and/or gas bearing formations by injecting an aqueous treatment fluid into at least one wellbore, wherein the aqueous treatment fluid is manufactured by mixing at least an aqueous base fluid with said homogeneous aqueous polyacrylamide concentrate at the site-of-use.

Abstract: Process for producing aqueous polyacrylamide concentrates by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel, comminuting said aqueous polyacrylamide gel and mixing it with an aqueous liquid, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide concentrate hold in a suitable transport unit from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide, wherein the units of the plant are located at two different locations A and B.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide gel from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide solutions wherein the units of the plant are located at two different locations A and B.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the process is carried out in a modular, relocatable plant. The plant preferably is deployed at a location at which aqueous polyacrylamide solutions are used, for example on an oilfield or in a mining area.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide gel hold in a transportable polymerization unit from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide solutions wherein the units of the plant are located at two different locations A and B.

Abstract: A process for producing an aqueous polymer solution, including: (a) providing a hydrated polymer that has been prepared by aqueous solution polymerisation of ethylenically unsaturated monomers, which hydrated polymer contains at least 10% by weight active polymer; (b) cutting the hydrated polymer by subjecting the hydrated polymer to at least one cutting stage containing at least one stream of aqueous liquid at a pressure of at least 150 bar to reduce the size of the hydrated polymer; and (c) dissolving the hydrated polymer in an aqueous liquid so as to obtain an aqueous polymer solution. An apparatus for producing an aqueous polymer solution.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide obtained by hydrolyzing acrylonitrile in water in the presence of a biocatalyst capable of converting acrylonitrile to acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide gel hold in a transportable polymerization unit from a location A to a location B. The aqueous polyacrylamide gel furthermore comprises at least one stabilizer for prevention of polymer degradation.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous monomer premix from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide solutions wherein the units of the plant are located at two different locations A and B.

Abstract: Process for producing aqueous polyacrylamide solutions by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide gel hold in a transportable polymerization unit from a location A to a location B. The transportable polymerization unit comprises a cylindrical upper part, a conical part at its lower end, feeds for the aqueous monomer solution, a closable bottom opening, and means allowing to deploy the polymerization unit in a vertical manner.

Abstract: Described herein is a process for preparing solid acrylic acid polymers including: (a) preparing an aqueous acrylic acid polymer solution having a solids content of 30% to 70% by weight by free-radical polymerization, (b) neutralizing the aqueous acrylic acid polymer solution at least partly by adding a base, which results in release of a heat of neutralization, and concentrating the aqueous acrylic acid polymer solution by exploiting the heat of neutralization to give a highly concentrated acrylic acid polymer solution having a solids content of 60% to 80% by weight, (c) shaping and drying the highly concentrated acrylic acid polymer solution.

Abstract: A process for producing an aqueous polymer solution, including: (a) providing a hydrated polymer that has been prepared by aqueous solution polymerisation of ethylenically unsaturated monomers, which hydrated polymer contains at least 10% by weight active polymer; (b) cutting the hydrated polymer by subjecting the hydrated polymer to at least one cutting stage containing at least one stream of aqueous liquid at a pressure of at least 150 bar to reduce the size of the hydrated polymer; and (c) dissolving the hydrated polymer in an aqueous liquid so as to obtain an aqueous polymer solution. An apparatus for producing an aqueous polymer solution.

Abstract: A method for preparing an aqueous polyacrylamide solution, where the method includes: hydrating acrylonitrile in water in presence of a biocatalyst capable of converting acrylonitrile to acrylamide so as to obtain an acrylamide solution; directly polymerizing the acrylamide solution so as to obtain a polyacrylamide gel; and directly dissolving the polyacrylamide gel by addition of water so as to obtain an aqueous polyacrylamide solution, wherein the polyacrylamide gel is dissolved by water jet cutting.

Abstract: A method for preparing an aqueous polyacrylamide solution is disclosed. The method comprises:—hydrating acrylonitrile in water in presence of a biocatalyst capable of converting acrylonitrile to acrylamide so as to obtain an acrylamide solution,—directly polymerizing the acrylamide solution so as to obtain a polyacrylamide gel, and—directly dissolving the polyacrylamide gel by addition of water so as to obtain an aqueous polyacrylamide solution.

Abstract: A mixer heat exchanger insert or mixer heat exchanger insert arrangement, and a mixer heat exchanger with a corresponding mixer heat exchanger insert arrangement, which have improved mixing and temperature-control behavior, and have a reduced fouling tendency.

Abstract: A mixer/heat exchanger insert or mixer/heat exchanger having a geometry which leads to less fouling of a fluid to be temperature-controlled.

Abstract: Polyamides based on dicarboxylic acids and on diamines are produced in a batch process by 1) feeding the entire amount of monomer composed of dicarboxylic acids, of diamines, and, if appropriate, of further polyamide-forming monomers, in the desired stoichiometry, in a closed stirred-tank reactor, 2) heating the monomer mixture in the stirred-tank reactor, with stirring, and with setting of a certain pressure, to a desired reaction temperature for the production of a prepolymer, 3) if appropriate, completely or partially depressurizing the reaction mixture from stage 2), 4) if appropriate, carrying out further thermal treatment of the reaction mixture from stage 2) or 3), and 5) reacting the reaction mixture from stage 2), 3), or 4) in the melt in a vented extruder for further increase of the molecular weight, with discharge of water vapor, and without use of additional polyamide-forming monomers or of polyamides.

Abstract: The present invention provides a process for producing polyamides, which comprises a) providing a monomer composition comprising at least one lactam or at least one aminocarbonitrile and/or oligomers of these monomers, b) reacting the monomer composition provided in step a) in a hydrolytic polymerization at elevated temperature in the presence of water to obtain a reaction product comprising polyamide, water, unconverted monomers and oligomers, c) the reaction product obtained in step b) being fed into at least one kneader (3) and subjected to a postpolymerization, d) optionally forming the reaction product obtained in step c) to obtain polyamide particles, e) optionally treating the reaction product obtained in step c) or the polyamide particles obtained in step d) with at least one extractant.

Abstract: In a process for producing polyamides by polycondensation of polycondensable polyamide-forming monomers and/or oligomers in reaction mixtures comprising same, which may be water-containing but are free from organic solvents, the polycondensation is effected in an agitated reactor under agitation in a first step in the liquid phase and after a phase change taking place during the process in the same reactor is effected in a subsequent second step in the solid state, wherein the temperature in the reactor is below the melting point of the polyamide in the second step at least.

Abstract: The present invention relates to the use of polyolefin copolymers A) for reducing color changes during the heating of polymer compositions which contain at least one thermoplastic polyamide B).