Method of inhibiting scale formation
AssigneeUnited States Filter Corporation
InventorRoy Martin
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Abstract
The present invention relates to the addition of an alkali salt form or a precipitated alkali salt form of a PESA, polymaleic acid or mixture thereof, which is added, directly and/or indirectly, to an oxidizer, e.g. calcium hypochlorite, to inhibit formation of scale, particularly calcium carbonate scale, when the oxidizer contacts water containing carbonate alkalinity. This provides effective inhibition of calcium carbonate in and on oxidizer feed equipment. Process efficiency is greatly enhanced by selecting, as the limiting factor, the concentration of alkalinity present that can be converted to carbonate ions (the carbonate alkalinity). Optimization of the feedrate of polymer based on the carbonate alkalinity results in effective scale inhibition at an LSI value greater than 3.5.
Claims9
A method for inhibition of calcium based scale in and on components of an oxidizer feed system in a water treatment process comprising:
- providing an alkaline hypochlorite oxidizer;
- providing an alkali salt form of polymer selected from the group consisting of calcium polyepoxysuccinic acid (PESA), magnesium PESA, sodium PESA, potassium PESA, lithium PESA, calcium polymaleate, magnesium polymaleate, sodium polymaleate, potassium polymaleate, lithium polymaleate and mixtures thereof;
- determining carbonate alkalinity of a source of water to be treated;
- forming an oxidizer feed solution including said oxidizer, said polymer and said source of water;
- maintaining said oxidizer feed solution at a weight ratio of the alkali salt form of polymer to carbonate based alkalinity within the range of from about 0.1:1 to about 2:1;
- and
- dispensing said solution into said water treatment process;
- whereby effective scale inhibition is achieved in said oxidizer system at LSI values greater than 3.5.
Dependencies are inferred from the claim text.