Hardness suppression in urea solutions
AssigneeNalco Fuel Tech
InventorsLeonard Dubin, W. Robert Epperly, Barry Normand Sprague, Thure von Harpe
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Abstract
The tendency of aqueous solutions of urea and other NH-containing compositions to force instability of hardness factors has been found to be detrimental to processes and apparatus employing them. The reliability of these processes and apparatus is improved by the inclusion of hardness-suppressing compositions, which preferably include both a water-soluble polymer and a phosphonate. In particular, agricultural and NO.sub.x -reducing applications are improved, especially for solutions containing urea hydrolysis products and the salts of them.
Claims9
A composition comprising water containing hardness factors, from 1 to 65% of a water-soluble NH-containing composition selected from the group consisting of ammonia, urea, urea precursors, urea hydrolysis products, carbamates, ammonium carbonate, ammonium bicarbonate, cyanurates, ammonium salts of organic acids, other amidozine-generating compositions and mixtures of these, and a hardness-suppressing composition comprising a member selected from the group of water soluble polymers effective to suppress hardness, water soluble phosphonates selected from the group consisting of organo phosphonates, amino phosphonates and amino polyphosphonates effective to suppress hardness, water soluble chelants effective to suppress hardness, water soluble phosphates effective to suppress hardness and mixtures of these, in an amount effective to moderate the tendency for precipitation of hardness factors.
Dependencies are inferred from the claim text.