Synergistic silica scale control

Abstract

A method for controlling colloidal / amorphous silica scale deposition in an aqueous system is described, which comprises adding to the aqueous system an effective amount of a synergistic combination comprising: A) 10% to 90% by weight of at least one carboxylate polymer comprising units derived from one or more carboxylate monomers; and B) 90% to 10% by weight of at least one chelating agent, based on the total weight of said synergistic combination. The carboxylate polymer may be a homopolymer of (meth)acrylic acid, maleic acid, itaconic acid, or their salts, or a copolymer of one or more monomers selected from meth)acrylic acid, maleic acid, itaconic acid, and their salts and, optionally, one or more sulfonic-free ethylenically unsaturated monomers. The chelating agent may be one or more of: methylamine, ethanolamine methylethanolamine (MEA), ethylenediamine (EDA), diethylenetriamine (DETA), ethylenediamine tetraacetic acid (EDTA), ethylenediamine disuccinic acid (EDDS), iminodiaacetic acid (IDA), tetrasodium ethylene diaminetetraacetic acid, and derivatives thereof, among others.

Description

technical field [0001] The present invention relates to a method of controlling the deposition of amorphous silica scale in aqueous systems having a neutral pH. The method includes adding an effective amount of a synergistic combination of at least one carboxylic acid or salt polymer and at least one chelating agent. Background technique [0002] The deposition and accumulation of silica scale on interior surfaces of water treatment equipment, such as boilers, cooling and purification systems, containing aqueous systems is problematic because it reduces heat transfer and fluid flow through such equipment. Accordingly, prevention of silica scale formation and deposition, and removal of such scale when deposited and accumulated, are of great concern to industries involved in water treatment. [0003] The formation of silica scale in aqueous systems is achieved by various properties of the aqueous system such as pH, temperature, metal ion concentration, and the like. These ch...

AI Technical Summary

Problems solved by technology

It is also known in the industry that there is no sulfonic acid group (-SO 2 OH) carboxylate homopolymers and copolymers, such as those also commercially available from The Dow Chemical Company under the tradenames ACUMER 1000 and ACUMER 4300, are generally less effective at avoiding silica scale deposition

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