Treatment of iron sulphide deposits
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Abstract
The present invention relates to a method of treating an aqueous system containing or in contact with metal sulphide scale. The method comprises adding to said system, separately or together, sufficient of a synergistic mixture comprising a THP+ salt, an aqueous solution of a strong acid (and optionally a source of nitrogen) to provide a solution containing from 0.1% to 30% by weight of the THP+ salt at a pH of less than about 1.0. The scale is contacted with said solution, (thereby dissolving at least part of said scale in said solution) and the dissolved scale is withdrawn from the system.
8 Citations
45 Claims
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1-25. -25. (canceled)
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26. A method of treating an aqueous system containing or in contact with metal sulphide scale, comprises the steps of:
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a) adding to said system, separately or together, sufficient of a synergistic mixture comprising a THP+ salt, an aqueous solution of a strong acid (and optionally a source of nitrogen) to provide a solution containing from 0.1% to 30% by weight of the THP+ salt at a pH of less than about 1.0, b) contacting said scale with said solution, thereby dissolving at least part of said scale in said solution, and c) withdrawing said dissolved scale from the system. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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43-1. The method according to claim 26, wherein the acid solution, the THP+ salt and the optional nitrogen source are formulated together prior to addition to the aqueous system.
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45. A formulation comprising:
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a synergistic mixture comprising between 0.1% and 50% by weight of the strong acid, between 0.1% and 30% by weight of the THP+ salt and between 0.1% and 10% by weight of the optional nitrogen source, and one or more additional water-treatment products selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, non-ionic surfactants, wetting agents, biocides, dispersants, demulsifiers, antifoams, solvents, scale inhibitors, corrosion inhibitors, gas hydrate inhibitors, asphaltene inhibitors, naphthenate inhibitors, oxygen scavengers and flocculants.
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Specification