JP5982809B2 - Water treatment equipment - Google Patents

Description

  The present invention relates to a water treatment apparatus that suppresses generation of precipitates on an inner wall of a pipe.

  In order to prevent the generation of scale, a method is known in which raw water is passed through a tank to form a precipitate, and the precipitate is returned to the upstream side of the tank as a seed crystal to remove scale material. For example, patent documents 1-4 are mentioned.

  Patent Document 1 discloses a method for treating geothermal water in which silica is recovered from geothermal water having a total dissolved salt concentration of 4000 to 30000 ppm and a dissolved silica concentration of 650 to 1200 ppm. After adding and precipitating supersaturated silica in geothermal water on the silica seed, the geothermal water and precipitated silica are separated, and then the colloidal silica in the separated supernatant is separated with an ultrafiltration membrane Disclosed is a method for treating geothermal water characterized by being collected.

  Patent Document 2 discloses a geothermal water supply means for supplying geothermal water, and a calcium compound that is at least one of calcium-containing oxides and hydroxides in the geothermal water from the geothermal water supply means. A calcium compound addition means, a reaction vessel for generating a precipitate in geothermal water by the addition of the calcium compound by the addition means, and a separation means for separating the produced precipitate, and further separated by the separation means A geothermal water treatment apparatus is provided, comprising a return means for returning a part of the sediment to the reaction tank.

  Patent Document 3 is a recovery device that recovers suspended solids in geothermal hot water, a tank in which the interior is partially partitioned, a flow path is provided, and hot water is stored in an upper part of the tank. And a container for collecting overflow water from the tank, and a feeding means for feeding the substance precipitated in the lower part of the tank to the container is provided between the tank and the container. And a return means for returning a part of the hot water in the container to the tank is provided between the tank and the container. An apparatus for recovering suspended solids from geothermal hot water is disclosed.

  Patent Document 4 was obtained by adding a seed having silica adsorptivity to an aqueous solution containing silica, adsorbing silica in the aqueous solution to the seed, and then solid-liquid separating the aqueous solution containing the seed. In the silica recovery method in an aqueous solution in which a part of solid content is reused as the seed, after adding calcium ions to the aqueous solution, the solution is allowed to stand for a predetermined time until the polymerization of silica proceeds, and the pH is adjusted to the alkali side. A method for recovering silica in an aqueous solution is disclosed in which a part of the precipitate thus obtained is reused as the seed.

Japanese Unexamined Patent Publication No. 63-1496 JP 2001-149953 A JP 2000-126753 A Japanese Patent Laid-Open No. 7-24475

  However, there is a problem that a large tank has to be prepared when the flow rate of raw water to be treated is large. When the acid or alkali is directly injected into the raw water, a large amount of acid or alkali has to be injected when the raw water flow rate is large.

  In view of the above-described problems, an object of the present invention is to provide a water treatment apparatus that can suppress the occurrence of precipitates on the inner wall of a pipe.

In order to achieve the above object, according to a first aspect of the present invention, in a water treatment apparatus that suppresses the generation of precipitates in a first pipe through which raw water flows, a first water flow rate of the first pipe is measured. A flow meter, a second pipe that returns the raw water branched off from the first pipe to the first pipe, a first pump installed in the second pipe, and a raw water flow rate of the second pipe are measured. a second flow meter, and a pH adjusting agent storage tank, and a second pump for adding a pH adjusting agent to the second pipe from the pH adjusting agent storage tank, pH value of the raw water after the addition of the pH adjusting agent is the A control unit is provided that controls the flow rate of the second pump based on the input pH value of the second pipe so as to approach a target pH value capable of rapidly growing precipitates in the second pipe. . The raw water contains a silica component exceeding the saturation concentration, and further contains calcium ions in the raw water. The water treatment apparatus further includes a pH meter for measuring the pH of the second pipe, and the control unit is configured to control the first pump at a flow rate set in advance with respect to the flow rate of the first flow meter. The flow rate of the second pump may be controlled based on the measured value of the pH meter so that the flow rate is controlled and the pH value of the raw water after the addition of the pH adjuster approaches the target pH value. More specifically, the pH meter may measure the pH of the raw water before the addition of the pH adjusting agent and feedforward control by the control unit, or the pH of the raw water after the addition of the pH adjusting agent. You may measure and feedback-control by a control part. The controller may control the flow rate of the first pump so that the particle diameter downstream of the first pipe is 0.3 μm or more. Moreover, the said control part may control the flow volume of a said 1st pump based on the target liquid feeding rate from which the scale adhesion to the said 1st piping decreases.

According to this configuration, a part of the fluid containing the precipitate grown in the first pipe is taken out at the branch point and returned to the upstream side of the first pipe as a return fluid. The pH is adjusted so that precipitates grow rapidly in the second pipe. When the precipitated particles are returned to the first pipe, the supersaturated component in the first pipe is likely to be deposited on the particle surface of the floating precipitate, so that the precipitate is generated on the inner wall of the first pipe. Can be suppressed. And since the flow rate of the fluid on the side to which the pH adjuster is added is small compared with the method of adding the pH adjuster directly to the fluid flowing through the first pipe and suppressing the generation of precipitates, the added amount of the pH adjuster Can be reduced. Moreover, according to this structure, the flow volume of a 2nd pump can be automatically controlled based on the measured value of a 1st flow meter, a 2nd flow meter, and a pH meter.

More specifically, the water treatment apparatus can make the position where the second pipe joins the first pipe downstream from the branch position.
According to this structure, it can suppress that a precipitate generate | occur | produces on the inner wall of 1st piping downstream from this water treatment apparatus.

Moreover, the said water treatment apparatus can also make the position which joins the said 1st piping of a said 2nd piping upstream from the said branch position.
According to this configuration, the size of the precipitate that floats while the precipitate circulates through the first pipe and the second pipe can be increased. The larger the size of the suspended precipitate, the more difficult it is to adhere to the pipe wall surface.

Also, the water treatment device, it is desirable to provide an input device for inputting data to the control unit.

  According to this configuration, input data can be changed at any time according to changes in the quality of raw water. The input data is the pH value or the target pH value of the second pipe. The input device is not an essential device, and these values may be stored as input values in the control unit in advance.

Also, the target pH value is desirably pH6.0 to 10.0 values.

According to this configuration, the generation rate of particles in the second pipe can be improved.
In the geothermal power generation apparatus including the water treatment apparatus, the raw water flowing through the first pipe is geothermal water, and the geothermal power generation apparatus generates electricity by extracting steam or heat from the geothermal water. It is desirable that the water treatment device is provided on the downstream side, and the first pipe downstream from the water treatment device is connected to a reduction well.

  According to this configuration, since the supersaturated silica is deposited on the floating precipitate, it is possible to suppress silica precipitation in the reduction well and to suppress the blocking of the reduction well. In addition, since the suspended solids are growing sufficiently large, the scale deposition rate in the reduction well is reduced, and the period until the reduction well is blocked can be extended.

  According to this invention, it can suppress that a precipitate generate | occur | produces in piping.

It is a schematic block diagram of the water treatment apparatus of one Embodiment of this invention. It is a schematic block diagram of the water treatment apparatus of other one Embodiment of this invention. It is a schematic block diagram of the electric power generating apparatus provided with the water treatment apparatus of one Embodiment of this invention.

  FIG. 1 is a schematic configuration diagram of a water treatment apparatus according to an embodiment of the present invention. The main water treatment apparatus 20a includes a first flowmeter 7 that measures the raw water flow rate of the first pipe L1, a second pipe L2a that returns the raw water branched and taken out from the first pipe L1 to the first pipe, and a second The first pump 1a installed in the pipe L2, the second flow meter 2a for measuring the raw water flow rate of the second pipe L2a, the pH meters 3a and 8a for measuring the pH of the second pipe L2a, and the pH adjusting agent storage tank 4a And the second pump 5a for adding the pH adjusting agent from the pH adjusting agent storage tank 4a to the second pipe L2a, and the measured value of the pH meter 8a so that the pH of the raw water after adding the pH adjusting agent approaches the target pH value. The control part 6a which controls the flow volume of the 2nd pump 5a based on is provided. The flow rate f2 (L / min) of the pH adjusting agent necessary to obtain the target pH is measured in advance with respect to the flow rate f1 (L / min) of the second pipe L2a, and the proportionality coefficient K = f2 / f1 is obtained. Keep it. In the control, the flow rate of the second pump 5a is controlled to be F1 × K (L / min) based on the input data of the measured value F1 (L / min) of the second flow meter 2a. Thus, the water flowing through the second pipe L2 is set as the target pH.

The flow rate f2 (L / min) of the pH adjusting agent may be feedback controlled so that the pH value of the pH meter 8a becomes the target pH.
The pH meter 8a is omitted, and the control unit 6a inputs the measured value of the pH of the second pipe L2a measured in advance so that the pH value of the raw water after adding the pH adjuster approaches the target pH value, The flow rate of the second pump 5a may be controlled based on this pH value. In this case, the water treatment apparatus preferably includes a keyboard as the input device 9 for inputting the measured value of the pH of the second pipe L2a to the control unit, and the display device 10 for displaying data of the control unit.

  The control unit 6 a arbitrarily sets a target liquid feeding rate in a range of 5% to 50% with respect to the flow rate of the first flow meter 7 in advance. The controller 6a controls the flow rate of the first pump 1a so as to achieve the target liquid feeding rate. The target liquid feed rate is determined by operating in advance by changing the return rate condition and finding the target liquid feed rate at which the scale adherence to the first pipe is reduced. Whether the scale adhesion to the first pipe is reduced may be determined by searching for a target liquid feeding rate at which the particle diameter downstream of the first pipe is 0.3 μm or more. When the particle diameter is 0.3 μm or more, the particles are less likely to adhere to the pipe, and therefore it is possible to suppress the generation of scale on the pipe inner wall downstream from the position where the second pipe and the first pipe merge.

  FIG. 2 is a schematic configuration diagram of a water treatment device 20b according to an embodiment of the present invention. The difference from FIG. 1 is that the position where the second pipe joins the first pipe is upstream from the branch position. There is no difference in other configurations, but some of the end numbers of sensors and devices have been changed.

  FIG. 3 is a schematic configuration diagram of a geothermal power generation apparatus including a water treatment apparatus according to an embodiment of the present invention. FIG. 3 shows the water treatment device 20 shown in FIG. 1 or 2 provided in a pipe between the geothermal power generation device 30 and the reduction well 22. The geothermal power generation device 30 takes in the gas-liquid mixed geothermal water flowing from the production well 21 into the gas-liquid separator 23. The gas-liquid separator 23 separates the gas-liquid mixed geothermal water into steam and hot water (hereinafter referred to as raw water).

  The separated steam is supplied to the turbine 24 and becomes power for rotating the turbine. The rotating shaft of the turbine 24 is connected to the generator 25, and the power generated by the rotation of the turbine 24 is converted into electricity by the generator 25. The electricity generated by the generator 25 is output to the outside. The steam exhausted from the outlet of the turbine 24 is supplied to the condenser 26, cooled and condensed to become water. The condensed water merges with the raw water and finally flows to the reducible 22 via the first pipe L1.

  One separated raw water (including the condensed water) is finally supplied to the reduction well 22 through the first pipe L1. The water treatment device 20 is installed in the middle of the first pipe L1. The hot water supplied from the gas-liquid separator 23 to the water treatment device 20 branches the raw water from the first pipe as shown in FIG. 1 or FIG. It is possible to suppress the generation of precipitates on the inner wall of the first pipe downstream from the water treatment device 20 by returning the seed crystal produced and returned to the first pipe.

  Although the present invention has been specifically described above based on the embodiments, the present invention is not limited to the embodiments and can be variously modified without departing from the gist thereof.

1a, 1b: 1st pump 2a, 2b: 2nd flow meters 3a, 3b, 8a, 8b: pH meter 4a, 4b: pH adjusting agent storage tank 5a, 5b: 2nd pumps 6a, 6b: control unit 7: 1st 1 flow meter 9: input device 10: display device L1: first piping L2a, L2b: second piping 20, 20a, 20b: water treatment device 21: production well 22: reduction well 23: gas-liquid separator 24: turbine 25 : Generator 26: Condenser 30: Geothermal power generator

Claims (8)

In the water treatment device that suppresses the generation of precipitates in the first pipe through which raw water flows,
A first flow meter for measuring the raw water flow rate of the first pipe;
A second pipe for returning the raw water taken out by branching out the first pipe to the first pipe;
A first pump installed in the second pipe;
A second flow meter for measuring the raw water flow rate of the second pipe;
a pH adjuster storage tank;
A second pump for adding a pH adjusting agent from the pH adjusting agent storage tank to the second pipe;
The pH value of the raw water after the addition of the pH adjuster is set to the input pH value of the second pipe so that the pH of the raw water approaches the target pH value that allows the precipitate to grow rapidly in the second pipe. A control unit for controlling the flow rate of the second pump based on :
A pH meter for measuring the pH of the second pipe;
The control unit controls the flow rate of the first pump at a preset flow rate with respect to the flow rate of the first flow meter,
The water treatment characterized in that the flow rate of the second pump is controlled based on the measured value of the pH meter so that the pH value of the raw water after the addition of the pH adjusting agent approaches the target pH value. apparatus. 2. The water treatment apparatus according to claim 1 , wherein the control unit controls a flow rate of the first pump so that a particle diameter downstream of the first pipe is 0.3 μm or more.

3. The water treatment apparatus according to claim 1, wherein the control unit controls the flow rate of the first pump based on a target liquid feeding rate at which scale adhesion to the first pipe is reduced. The position where the second pipe joins the first pipe is downstream from the branch position.
The water treatment apparatus according to any one of claims 1 to 3, wherein The position where the second pipe joins the first pipe is upstream from the branch position.
The water treatment apparatus according to any one of claims 1 to 3, wherein The water treatment apparatus according to any one of claims 1 to 5, further comprising an input device that inputs data of the control unit. The water treatment apparatus according to any one of claims 1 to 6, wherein the target pH value is a value of pH 6.0 or more and 10.0 or less. The raw water flowing through the first pipe is geothermal water, and the water treatment device includes the water treatment device on the downstream side of a geothermal power generation device that generates steam or heat from the geothermal water to generate electricity. The geothermal power generation apparatus including the water treatment apparatus according to any one of claims 1 to 6, wherein the first pipe located further downstream is connected to a reduction well.

Images