Process for producing aqueous polyacrylamide solutions

A process for producing an aqueous polyacrylamide solution comprising polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel and dissolving said aqueous polyacrylamide gel in water, characterized in that the process is conducted in a modular, relocatable plant and the process comprises at least the following steps:

• [1] Preparing—in a relocatable monomer make-up unit—an aqueous monomer solution comprising at least water and 5% to 45% by weight—relating to the total of all components of the aqueous monomer solution—of water-soluble, monoethylenically unsaturated monomers, wherein said water-soluble, monoethylenically unsaturated monomers comprise at least acrylamide,
• [2] Inerting and radically polymerizing the aqueous monomer solution prepared in step [1] in the presence of suitable initiators for radical polymerization under adiabatic conditions, wherein
• the polymerization is performed in a relocatable polymerization unit having a volume of 1 m3 to 100 m3,
• the aqueous monomer solution before the onset of polymerization has a temperature T1 not exceeding 30° C., and
• the temperature of the polymerization mixture raises in course of polymerization—due to the polymerization heat generated—to a temperature T2 of at least 45° C.,
• thereby obtaining an aqueous polyacrylamide gel having a temperature T2 which is held in the relocatable polymerization unit,
• [3] removing the aqueous polyacrylamide gel from the relocatable polymerization unit,
• [4] comminuting the aqueous polyacrylamide gel by conveying the aqueous polyacrylamide gel through at least one relocatable comminuting unit, thereby obtaining aqueous polyacrylamide gel pieces, and
• [5] dissolving the aqueous polyacrylamide gel pieces in an aqueous liquid in a relocatable dissolution unit, thereby obtaining an aqueous polyacrylamide solution.