WATER TREATMENT SYSTEM, WATER TREATMENT METHOD, COOLING FACILITY AND POWER GENERATING FACILITY
A water treatment system provided with: a first scale inhibitor-supplying unit which supplies a scale inhibitor to a blowdown water, the blowdown water being water to be treated that is generated in a cooling tower and contains at least a salt and silica; a first pH-adjusting unit which adjusts the pH of the blowdown water, to which the scale inhibitor has been supplied using a pH adjusting agent; a first desalinating apparatus which is provided downstream of the first pH-adjusting unit, removes the salt in the blowdown water, and separates the water into a first reclaimed water and a first concentrated water; and a first crystallizing unit which is provided downstream of the first desalinating apparatus and has a first crystallizing tank for calcium sulfate from the first concentrated water and a first seed crystal-supplying unit for supplying calcium sulfate seed crystals of calcium sulfate to the first crystallizing tank.
1 . A water treatment system comprising:
a first scale inhibitor-supplying unit, which supplies a scale inhibitor to water to be treated that contains at least a salt and silica;
a first pH-adjusting unit, which adjusts a pH of the water to be treated to which the scale inhibitor has been supplied using a pH-adjusting agent;
a first desalinating apparatus, which is provided downstream of the first pH-adjusting unit and removes salts in the water to be treated and separates the water into first reclaimed water and first concentrated water; and
a first crystallizing unit including
a first crystallizing tank, which is provided downstream of the first desalinating apparatus and crystallizes calcium sulfate from the first concentrated water, and
a first seed crystal-supplying unit, which supplies seed crystals of calcium sulfate to the first crystallizing tank.
2 . A water treatment system comprising:
a first scale inhibitor-supplying unit, which supplies a scale inhibitor to water to be treated that contains at least a salt and silica;
a first pH-adjusting unit, which adjusts a pH of the water to be treated to which the scale inhibitor has been supplied using a pH-adjusting agent;
a first desalinating apparatus, which is provided downstream of the first pH-adjusting unit and removes salts in the water to be treated and separates the water into first reclaimed water and first concentrated water;
a first crystallizing unit, which has a first crystallizing tank, which is provided downstream of the first desalinating apparatus and crystallizes calcium sulfate from the first concentrated water,
and a first seed crystal-supplying unit, which supplies seed crystals of calcium sulfate to the first crystallizing tank;
a first separating unit, which is provided downstream of the first crystallizing unit and separates calcium sulfate in the first concentrated water;
a second scale inhibitor-supplying unit, which supplies a scale inhibitor to the first concentrated water from which calcium sulfate has been separated;
a second pH-adjusting unit, which adjusts a pH of the first concentrated water to which the scale inhibitor has been supplied; and
a second desalinating apparatus, which is provided downstream of the second pH-adjusting unit and removes salts in the first concentrated water and separates the water into second reclaimed water and second concentrated water.
3 . The water treatment system according to claim 2 , further comprising:
a second crystallizing unit, which has a second crystallizing tank, which is provided downstream of the second desalinating apparatus and crystallizes calcium sulfate from the second concentrated water,
and a second seed crystal-supplying unit, which supplies seed crystals of calcium sulfate to a second crystallizing tank.
4 . The water treatment system according to claim 2 , further comprising:
a second crystallizing unit, which has a second crystallizing tank, which is provided downstream of the second desalinating apparatus and crystallizes calcium sulfate from the second concentrated water,
and a second seed crystal-supplying unit, which supplies seed crystals of calcium sulfate to the second crystallizing tank;
a second separating unit, which is provided downstream of the second crystallizing unit and separates calcium sulfate in the second concentrated water; and
a third desalinating apparatus, which removes salts in the second concentrated water and separates the water into third reclaimed water and third concentrated water.
5 . The water treatment system according to claim 1 , wherein,
when the pH is adjusted to not less than 10 by the first pH-adjusting unit or second pH-adjusting unit, calcium scale inhibitor which inhibits deposition of scale containing calcium is supplied from the first or second scale inhibitor-supplying unit.
6 . The water treatment system according to claim 1 , wherein,
when the pH is adjusted to not greater than 10 by the first pH-adjusting unit or second pH-adjusting unit, calcium scale inhibitor which inhibits deposition of scale containing calcium and silica scale inhibitor which inhibits deposition of silica are supplied from the scale inhibitor-supplying unit.
7 . The water treatment system according to claim 1 , further comprising:
one or both of a settling unit, which decreases a calcium carbonate concentration in the water to be treated, and a carbon dioxide gas separating unit, which separates carbon dioxide gas, that are provided upstream of the first or second scale inhibitor-supplying unit.
8 . The water treatment system according to claim 1 , wherein,
the reclaimed water is used as makeup water or recycled water of a plant facility.
9 . A cooling facility comprising the water treatment system described in claim 1 .
10 . A power generating facility comprising the cooling facility described in claim 9 .
11 . A water treatment method comprising the steps of:
a first scale inhibitor-supplying step, in which a scale inhibitor is supplied to water to be treated that contains at least a salt and silica;
a first pH-adjusting step, in which a pH of blowdown water to which the scale inhibitor has been supplied is adjusted using a pH-adjusting agent;
a first desalinating step, which is provided downstream of the first pH-adjusting step and in which salts in the blowdown water are removed and the water is separated into first reclaimed water and first concentrated water;
a first crystallizing step, which is provided downstream of the first desalinating step and in which calcium sulfate is crystallized from the first concentrated water; and
a first seed crystal-supplying step, in which seed crystals of calcium sulfate are supplied to a first crystallizing tank.
12 . A water treatment method comprising the steps of:
a first scale inhibitor-supplying step, in which a scale inhibitor is supplied to water to be treated that contains at least a salt and silica;
a first pH-adjusting step, in which a pH of blowdown water to which the scale inhibitor has been supplied is adjusted using a pH-adjusting agent;
a first desalinating step, which is provided downstream of the first pH-adjusting step and in which salts in the blowdown water are removed and the water is separated into first reclaimed water and first concentrated water;
a first crystallizing step, which is provided downstream of the first desalinating step and in which calcium sulfate is crystallized from the first concentrated water and;
a first seed crystal-supplying step, in which seed crystals of calcium sulfate are supplied to a first crystallizing tank;
a first separating step, which is provided downstream of the first crystallizing step and in which calcium sulfate in the first concentrated water is separated;
a second scale inhibitor-supplying step, in which a scale inhibitor is supplied to the first concentrated water from which calcium sulfate has been separated;
a second pH-adjusting step, in which a pH of the first concentrated water to which the scale inhibitor has been supplied is adjusted; and
a second desalinating step, which is provided downstream of the second pH-adjusting step and in which salts in the first concentrated water are removed and the water is separated into second reclaimed water and second concentrated water.
13 . The water treatment method according to claim 12 , further comprising the steps of:
a second crystallizing step, which is provided downstream of the second desalinating step and in which calcium sulfate is crystallized from the second concentrated water; and
a second seed crystal-supplying step, in which seed crystals of calcium sulfate are supplied to a second crystallizing tank.
14 . The water treatment method according to claim 12 , further comprising the steps of:
a second crystallizing step, which is provided downstream of the second desalinating step and in which calcium sulfate is crystallized from the second concentrated water;
a second seed crystal-supplying step, in which seed crystals of calcium sulfate are supplied to the second crystallizing tank;
a second separating step, which is provided downstream of the second crystallizing step and in which calcium sulfate in the second concentrated water is separated; and
a third desalinating step in which salts in the second concentrated water are removed and the water is separated into third reclaimed water and third concentrated water.
15 . The water treatment method according to claim 11 , wherein
when the pH is adjusted to not less than 10 by the first or second pH-adjusting step, calcium scale inhibitor which inhibits deposition of scale containing calcium is supplied in the scale inhibitor-supplying step.
16 . The water treatment method according to claim 11 , wherein
when the pH is adjusted to not greater than 10 by the first or second pH-adjusting step, calcium scale inhibitor which inhibits deposition of scale containing calcium and silica scale inhibitor which inhibits deposition of silica are supplied in the scale inhibitor-supplying step.
17 . The water treatment method according to claim 11 , further comprising:
one or both of a settling step, in which a calcium carbonate concentration in the blowdown water is decreased, and a carbon dioxide gas separating step, in which carbon dioxide gas is separated, provided upstream of the first or second scale inhibitor-supplying step.
18 . The water treatment method according to claim 11 , wherein
the reclaimed water is used as makeup water or recycled water of a plant facility.