Water treatment process and water treatment system
First Claim
1. A water treatment process comprising:
- a first scale inhibitor supplying step of supplying a calcium scale inhibitor which is a scale inhibitor for inhibiting the deposition of a scale containing calcium to water containing Ca2+ ions, SO42−
ions, carbonate ions and silica;
a first pH adjusting step of adjusting the water to a pH of 10 or more at which the silica is soluble in the water;
a first demineralizing step of separating the water into first concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water after the first scale inhibitor supplying step and the first pH adjusting step; and
a first crystallizing step of supplying seed crystals of gypsum to the first concentrated water so that gypsum is crystallized from the first concentrated water,wherein the water treatment process further comprises, after the first crystallizing step;
a second scale inhibitor supplying step of supplying the calcium scale inhibitor and a silica scale inhibitor which is a scale inhibitor for inhibiting the deposition of the silica to the water;
a second demineralizing step of separating the water into second concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water after the second scale inhibitor supplying step; and
a second crystallizing step of supplying seed crystals of gypsum to the second concentrated water so that gypsum is crystallized from the second concentrated water.
2 Assignments
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Accused Products
Abstract
In a water treatment system and a water treatment process, a scale inhibitor is supplied to water to be treated containing Ca ions, SO4 ions, carbonate ions, and silica, and the water to be treated is adjusted to a pH at which silica is soluble. The pH-adjusted water containing the calcium scale inhibitor is separated in a first demineralizing section into concentrated and treated water. In a first crystallizing section, seed crystals of gypsum are supplied to the first concentrated water, whereby gypsum is crystallized and removed from the first concentrated water. Silica in the water to be treated is removed from the first concentrated water on the downstream side of the first crystallizing section. Calcium carbonate in the water to be treated is removed from the first concentrated water on the upstream side of the first demineralizing section or the downstream side of the first crystallizing section.
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Citations
34 Claims
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1. A water treatment process comprising:
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a first scale inhibitor supplying step of supplying a calcium scale inhibitor which is a scale inhibitor for inhibiting the deposition of a scale containing calcium to water containing Ca2+ ions, SO42−
ions, carbonate ions and silica;a first pH adjusting step of adjusting the water to a pH of 10 or more at which the silica is soluble in the water; a first demineralizing step of separating the water into first concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water after the first scale inhibitor supplying step and the first pH adjusting step; anda first crystallizing step of supplying seed crystals of gypsum to the first concentrated water so that gypsum is crystallized from the first concentrated water, wherein the water treatment process further comprises, after the first crystallizing step; a second scale inhibitor supplying step of supplying the calcium scale inhibitor and a silica scale inhibitor which is a scale inhibitor for inhibiting the deposition of the silica to the water; a second demineralizing step of separating the water into second concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water after the second scale inhibitor supplying step; anda second crystallizing step of supplying seed crystals of gypsum to the second concentrated water so that gypsum is crystallized from the second concentrated water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A water treatment system comprising:
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a first scale inhibitor supplying section that supplies a calcium scale inhibitor which is a scale inhibitor for inhibiting the deposition of a scale containing calcium to water containing Ca2+ ions, SO42−
ions, carbonate ions and silica;a first pH adjusting section that supplies a pH adjuster to the water to adjust the pH of the water to be treated to 10 or more such that the silica is soluble in the water; a first demineralizing section that is installed on a downstream side of the first scale inhibitor supplying section and the first pH adjusting section and separates the water into first concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water; anda first crystallizing section including a first crystallizing tank that is installed on a downstream side of the first demineralizing section and crystallizes gypsum from the first concentrated water and a first seed crystal supplying section that supplies seed crystals of gypsum to the first crystallizing tank, wherein the water treatment system further comprises, on a downstream side of the first crystallizing section; a second scale inhibitor supplying section that supplies the calcium scale inhibitor and a silica scale inhibitor which is a scale inhibitor for inhibiting the deposition of silica to the water; a second demineralizing section that is installed on a downstream side of the second scale inhibitor supplying section and separates the water into second concentrated water in which the Ca2+ ions, the SO42−
ions, the carbonate ions and the silica are concentrated and treated water; anda second crystallizing section including a second crystallizing tank that is installed on a downstream side of the second demineralizing section and crystallizes gypsum from the second concentrated water and a second seed crystal supplying section that supplies seed crystals of gypsum to the second crystallizing tank. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification