JP2014001085A - Recovery system and recovery method of sodium hydrogen carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To collect sodium hydrogen carbonate included in ground water.SOLUTION: Ground water is concentrated by an evaporation-type concentrator 4. The concentrated ground water is contacted with carbon dioxide by a carbon dioxide absorption-type crystallizer 5 and sodium hydrogen carbonate crystallizes and precipitates. Recovery percentage of the sodium hydrogen carbonate is raised by introducing carbon dioxide generated by the evaporation-type concentrator 4 into the concentrated ground water of the carbon dioxide absorption-type crystallizer 5.

Description

  The present invention relates to an apparatus and method for recovering sodium hydrogen carbonate contained in groundwater, and more particularly, suitable for recovering sodium hydrogen carbonate contained in groundwater such as associated water generated when collecting coalbed methane gas or the like. The present invention relates to an apparatus and a recovery method.

  In recent years, utilization of coal bed methane gas that can be collected from the coal bed has been advanced. The accompanying water generated in a large amount when collecting the coal bed methane gas contains sodium chloride, sodium bicarbonate, sodium carbonate and the like.

  As the accompanying water contains salt, it cannot be used as irrigation water or drained into rivers. For this reason, treatment such as temporary storage in a pond and volume reduction by natural evaporation is performed. It is.

  However, the evaporating pond system that is stored in a reservoir and spontaneously evaporates requires a vast site.

  Therefore, in order to significantly reduce the installation capacity compared to the evaporating basin method, for example, Patent Document 1 proposes a concentrating device that combines a desalinating device using a reverse osmosis membrane and a concentrating device using an evaporation method. ing.

WO 2012/008013

  According to the concentrating device of Patent Document 1, the capacity of the accompanying water can be reduced by greatly reducing the equipment capacity, but the treatment of the concentrated water after the volume reduction is not easy. Therefore, it is desired to collect and collect effective soda components contained in the concentrated water. However, the above Patent Document 1 does not disclose such collection of soda components.

  This invention is made | formed in view of the above points, Comprising: It aims at collect | recovering sodium hydrogencarbonate which is a soda component contained in groundwater, such as accompanying water.

  In order to achieve the above object, the present invention is configured as follows.

  (1) The sodium hydrogen carbonate recovery device of the present invention is a device for recovering the sodium hydrogen carbonate from ground water containing at least sodium carbonate, sodium hydrogen carbonate and sodium chloride, and concentrating the ground water Carbon dioxide gas generated by the evaporative concentrator, and a carbon dioxide absorption crystallizer that precipitates sodium hydrogencarbonate crystals by bringing the concentrated groundwater concentrated by the evaporative concentrator into contact with carbon dioxide. Is introduced into the concentrated groundwater in the carbon dioxide absorption crystallization apparatus.

  According to the present invention, when carbonic acid gas generated by the evaporation type concentrating device is precipitated from the concentrated ground water evaporated and evaporated by the carbon dioxide absorption type crystallizing device, the carbon dioxide absorption type crystallizing device is used. Therefore, the production of hydrogen carbonate ions is promoted in the concentrated ground water, and the recovery rate of sodium hydrogen carbonate can be increased.

  (2) In a preferred embodiment of the present invention, the reverse osmosis membrane is provided with a reverse osmosis membrane type concentration device that separates the groundwater before concentration supplied to the evaporation type concentration device into permeated water and membrane concentrated water. The membrane concentrated water separated by the type concentrator is supplied to the evaporating type concentrator as ground water before concentration.

  According to this embodiment, the groundwater is concentrated by the reverse osmosis membrane type concentrator and further evaporated and concentrated by the evaporative type concentrator, so that the groundwater can be efficiently concentrated.

  (3) The sodium hydrogen carbonate recovery device of the present invention is a device for recovering the sodium hydrogen carbonate from ground water containing at least sodium carbonate, sodium hydrogen carbonate and sodium chloride, and concentrating the ground water A carbon dioxide absorption crystallizer for bringing the concentrated groundwater concentrated by the evaporative concentrator into contact with carbon dioxide, thereby precipitating sodium hydrogencarbonate crystals, and before the concentration supplied to the evaporative concentrator A reverse osmosis membrane type concentrating device that separates the groundwater into permeated water and membrane concentrated water, and removing carbon dioxide contained in the permeated water separated by the reverse osmosis membrane type concentrating device; While introducing into the concentrated groundwater in the absorption crystallization apparatus, the membrane concentrated water separated by the reverse osmosis membrane type concentration apparatus is transferred to the evaporative concentration apparatus before being concentrated. And supplies as.

  Since the groundwater as raw water contains a large amount of carbonate ions, the permeated water separated by the reverse osmosis membrane type concentrator preceding the evaporation type concentrator also contains a large amount of carbon dioxide. This carbon dioxide gas can be taken out from the permeated water by, for example, a vacuum deaerator.

  According to the present invention, carbon dioxide contained in the permeated water separated by the reverse osmosis membrane type concentrator when the sodium hydrogen carbonate crystals are precipitated from the evaporated and concentrated concentrated groundwater by the carbon dioxide absorption type crystallizer. Since it is taken out and introduced into and brought into contact with the concentrated groundwater of the carbon dioxide absorption crystallizer, the generation of hydrogencarbonate ions is promoted in the concentrated groundwater, and the recovery rate of sodium bicarbonate can be increased.

  Further, since the groundwater is concentrated by the reverse osmosis membrane type concentrator and further evaporated and concentrated by the evaporation type concentrator, the groundwater can be efficiently concentrated.

  (4) In a preferred embodiment of the present invention, a heat recovery device is provided that preheats the groundwater before concentration supplied to the evaporative concentrator with heat of the concentrated groundwater concentrated by the evaporative concentrator.

  According to this embodiment, since the groundwater before concentration supplied to the evaporative concentrator is preheated by the heat of the concentrated groundwater that has been concentrated and heated in the evaporative concentrator, the heat of the concentrated groundwater is recovered. Energy efficiency. Since the temperature of concentrated groundwater decreases, the solubility of sodium hydrogen carbonate can be lowered and the recovery rate of the crystals can be increased. Further, the concentrated groundwater discharged from the heat recovery device may be further cooled by chiller water.

  (5) In still another embodiment of the present invention, the groundwater is associated water discharged together with carbon dioxide from the coal bed.

  The associated water discharged together with carbon dioxide from the coal bed has a pH of about 8 to 9, and according to this embodiment, sodium bicarbonate contained in the associated water is recovered without adjusting the pH of the associated water. be able to.

  (6) The method for recovering sodium bicarbonate of the present invention is a method for recovering the sodium bicarbonate from groundwater containing at least sodium carbonate, sodium bicarbonate and sodium chloride, and evaporating and concentrating the groundwater; The step of bringing the concentrated groundwater evaporated and concentrated in the step into contact with carbon dioxide to precipitate crystals of sodium hydrogen carbonate. In the step of precipitating, the carbon dioxide generated in the step of evaporating and concentrating is concentrated in the concentration step. Introduced into groundwater.

  According to the present invention, when depositing sodium bicarbonate crystals from the concentrated groundwater that has been evaporated and concentrated, the carbon dioxide gas generated during the evaporation and concentration is introduced into the concentrated groundwater. Can be promoted to increase the recovery rate of sodium hydrogen carbonate.

  (7) The method for recovering sodium hydrogen carbonate according to the present invention is a method for recovering the sodium hydrogen carbonate from ground water containing at least sodium carbonate, sodium hydrogen carbonate and sodium chloride, and permeates the ground water through a reverse osmosis membrane. A step of separating water into membrane concentrated water, a step of evaporating and concentrating the separated membrane concentrated water to obtain concentrated groundwater, and contacting the evaporated concentrated groundwater with carbon dioxide gas to form sodium bicarbonate. A step of precipitating crystals, and in the step of precipitating, carbon dioxide gas contained in the permeated water separated by the reverse osmosis membrane is taken out and introduced into the concentrated groundwater.

  According to the present invention, when precipitating sodium bicarbonate crystals from the concentrated groundwater that has been evaporated and concentrated, the carbon dioxide gas contained in the permeated water separated by the reverse osmosis membrane is taken out and introduced into the concentrated groundwater. The production of hydrogen carbonate ions is promoted in the groundwater, and the recovery rate of sodium hydrogen carbonate can be increased.

  As described above, according to the present invention, when the sodium hydrogen carbonate crystals are precipitated from the evaporated and concentrated concentrated groundwater by the carbon dioxide absorption crystallizer, the carbon dioxide gas generated by the evaporator or the reverse osmosis is generated. Since the carbon dioxide gas contained in the permeated water separated by the membrane concentrator is introduced into the concentrated groundwater, the production of hydrogen carbonate ions is promoted in the concentrated ground water, and the recovery rate of sodium hydrogen carbonate can be increased.

FIG. 1 is an overall configuration diagram of a collection device according to an embodiment of the present invention. FIG. 2 is a block diagram of the evaporative concentration apparatus of FIG. FIG. 3 is a schematic configuration diagram of the heat recovery apparatus of FIG. FIG. 4 is a block diagram of the carbon dioxide absorption crystallization apparatus of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a sodium hydrogen carbonate recovery device according to an embodiment of the present invention.

  The recovery device 1 of this embodiment uses as its raw water the accompanying water generated in large quantities when groundwater, for example, coal seam gas is collected from the coal seam, and recovers sodium hydrogen carbonate contained in this raw water. It is.

  The raw water contains sodium chloride, sodium hydrogen carbonate, and sodium carbonate as main components, and the recovery device 1 recovers sodium hydrogen carbonate contained in the raw water. The pH of this raw water is about 8-9, and there is no need to adjust the pH during recovery.

  The recovery device 1 includes a reverse osmosis membrane type concentration device 2 that separates groundwater into permeated water (fresh water) and non-permeated water, and raw water that is non-permeated water membrane-concentrated by the reverse osmosis membrane type concentration device 2. , And an evaporative concentration device 4 that concentrates the raw water preheated by the heat recovery device 3 to near saturation or supersaturation and sends it to the heat recovery device 3. A carbon dioxide absorption crystallizer 5 for concentrating the concentrated raw water concentrated in the evaporative concentration device 4 and recovered in the heat recovery device 3 with carbon dioxide to precipitate sodium hydrogen carbonate crystals, and carbon dioxide And a solid-liquid separator 6 for separating the sodium hydrogen carbonate crystals precipitated by the absorption crystallizer 5. The carbon dioxide gas generated by the evaporation type concentrator 4 is introduced into the carbon dioxide absorption crystallizer 5 as will be described later.

  The reverse osmosis membrane evaporator 2 is supplied with raw water (ground water) that has been subjected to a pretreatment such as removal of ions that make a hardly soluble salt such as calcium, magnesium, barium, and strontium by a pretreatment device (not shown). , Separated into permeate and non-permeate. The permeated water is used as fresh water, and the membrane-permeated non-permeated water is supplied to the heat recovery device 3 to be preheated and supplied to the evaporative concentration device 4.

  The evaporation type concentration apparatus 4 of this embodiment is a two-effect horizontal tube thin film flow type evaporation apparatus shown in FIG. The evaporative concentrator 4 is not limited to a dual effect, and may be a single effect or a multi-effect evaporator having three or more effects, or a self-evaporating vapor mechanical compression evaporator that does not use steam.

  This evaporative concentrator 4 includes a first effect evaporator 7 and a second effect evaporator 8. Each of the evaporators 7 and 8 is provided with a plurality of heat transfer tubes 7a and 8a substantially horizontally in the upper portion thereof, and pumps raw water supplied to the lower portion thereof on the outer surface of the heat transfer tubes 7a and 8a. Circulation pipes 31 and 32 that circulate so as to be sprayed are provided, and first and second circulation pumps 9 and 10 are installed in the respective circulation pipes 31 and 32, respectively.

  The raw water preheated by the heat recovery device 3 is supplied to the lower part of the first effect evaporator 7 through the supply pipe 11, and a part of the raw water in the first effect evaporator 7 is circulated as described above. On the other hand, the remaining part is supplied to the lower part of the second effect evaporator 8 through the pipe 12.

  Further, one end of each heat transfer tube 7a, 8a of each evaporator 7, 8 communicates with the inlet side header 7b, 8b, and the other end communicates with the outlet side header 7c, 8c.

  A part of the steam from the second effect evaporator 8 is sucked and compressed by a steam ejector 14 driven by steam supplied from a heat source such as a boiler (not shown) through the steam duct 13 and then passed through the steam duct 15. Is supplied to the inlet side header 7b of the first effect evaporator 7 and becomes a heat source for evaporating the raw water in the first effect evaporator 7. The steam generated in the first effect evaporator 7 is supplied to the inlet side header 8b of the second effect evaporator 8 through the steam duct 16, and becomes a heat source for evaporating the raw water in the second effect evaporator 2. .

  A part of the steam generated in the second effect evaporator 8 is supplied to the steam ejector 14 as described above, while the remaining part is supplied to the condenser 17 via the branch duct 27 and cooled. Condensed. The condensed water is discharged by the condensed water pump 30. The condenser 17 is connected to a vacuum pump 29 for depressurizing each of the evaporators 7, 8 and the like.

  In this evaporation type concentrator, the raw water supplied into the first effect evaporator 7 from the heat recovery device 3 through the supply line 11 is concentrated by heating and evaporation here, and then is supplied to the second effect evaporator 8. Sent and further concentrated by heating and evaporation.

  Normally, the first effect evaporator 7 is operated at a temperature of 100 to 60 ° C., and the second effect evaporator 8 is operated at a slightly lower temperature. In this embodiment, the temperature of the concentrated raw water concentrated in the first effect evaporator 7 is about 68 ° C., and the temperature of the concentrated raw water concentrated in the second effect evaporator 8 is about 65 ° C. .

  A part of the concentrated raw water concentrated in the second effect evaporator 8 is circulated through the circulation pipe 32, while the remainder is supplied to the heat recovery device 3. The heat is recovered by exchanging heat with the raw water from the reverse osmosis membrane type concentrator 2.

In this evaporative concentration apparatus 4, carbon dioxide gas (CO ₂ ) is generated during evaporative concentration. This carbon dioxide gas is recovered and supplied to the carbon dioxide absorption crystallization apparatus 5. Specifically, the mixed gas of carbon dioxide and steam is supplied to the condenser 17 via the branch duct 27 branched from the steam duct 28 at the upper part of the second effect evaporator 8 and is cooled to remove the accompanying steam. Then, it is supplied to the carbon dioxide absorption crystallization apparatus 5 through a water-sealed vacuum pump 29.

As shown in the schematic diagram of FIG. 3, the heat recovery device 3 of this embodiment is configured by a multi-stage, for example, seven-stage flash evaporator, and has an opening 3 ₁ a for circulating raw water concentrated in the lower part. Equipped with reduced-pressure evaporation chambers 3 _{1 to} 3 ₇ having ˜3 ₇ a, the concentrated raw water concentrated in the evaporative concentrator 4 is sequentially introduced and flash-evaporated, while the evaporated steam is supplied to the upper preheating line It cools with the raw | natural water of the low temperature from the reverse osmosis membrane type | mold concentration apparatus 2 which distribute | circulates 18. Thus, heat exchange between the hot concentrated raw water and the low temperature raw water is performed, the heat of the hot concentrated raw water is recovered, and the preheated raw water is supplied to the evaporative concentrator 4.

  The temperature of the concentrated raw water supplied from the second effect evaporator 8 of the evaporation type concentrating device 4 to the heat recovery device 3 is about 65 ° C., and flash evaporation is repeated in the heat recovery device 3 so that the reverse osmosis membrane type concentration device. The temperature of the concentrated raw water after preheating the raw water from 2 is reduced to about 40 ° C.

  Thus, since the heat | fever of the concentration raw | natural water concentrated with the evaporative concentration apparatus 4 is collect | recovered, energy efficiency can be improved.

  As the heat recovery device 3, a heat exchanger may be used in place of the flash evaporator, but the concentrated groundwater is saturated or supersaturated with carbonate, so that the crystals are brought into the heat transfer surface with cooling. Precipitate. Furthermore, since the raw water contains silica, the concentrated raw water concentrated by the evaporative concentration device 4 has a high silica concentration. In the heat exchanger, the silica is reduced as the temperature of the concentrated raw water decreases. As a result, the scale is attached to the heat exchange surface and the heat exchange efficiency decreases. For this reason, in this embodiment, a flash evaporator is used.

  The carbon dioxide absorption crystallization apparatus 5 of this embodiment uses a jacket cooling type crystallization apparatus.

  As shown in FIG. 4, the carbon dioxide absorption crystallization apparatus 5 has a jacket 19a around a crystal can 19 for crystallization, and circulates cold water from a chiller (not shown) in the jacket 19a. Cool through the wall of the can 19. The temperature of the concentrated raw water in the crystal can 19 is cooled to 15 ° C. to 20 ° C. and maintained.

  The crystal can 19 has a cylindrical shape at the top and a cone shape at the bottom for classification. The concentrated raw water cooled by the heat recovery device 3 is supplied to the bottom via the supply line 22. Is done.

  Further, a slurry containing precipitated sodium hydrogencarbonate crystals is taken out from the bottom of the crystal can 19, and a part of the slurry is supplied to the solid-liquid separator 6, while the remainder is generated in the evaporation type concentrator 4. Carbon dioxide gas is sucked and mixed by the ejector 25 and introduced into the lower portion of the crystal can 19.

As a result, the concentrated stock solution in the crystal can 19 is agitated, and the carbon dioxide gas dissolves as fine bubbles in the entire crystal can 19, the pH slightly decreases, and the ratio of the carbonate ion (CO ₃ ⁻ ) component decreases. To do. Thus it reduces the pH, because the component ratio of sodium carbonate (Na ₂ CO ₃₎ is reduced, it is possible to sodium carbonate is prevented from crystallizing.

Further, the carbon dioxide gas generated in the evaporation type concentrator 4 is recovered and introduced into the crystal can 19, and the carbon dioxide gas dissolved in the concentrated raw water generates new hydrogen carbonate ions (HCO ₃ ⁻ ). The recovery rate of sodium can be increased.

  The slurry containing sodium hydrogencarbonate crystals taken out from the bottom of the crystal can 19 is supplied to the solid-liquid separator 6 in FIG.

  Examples of the solid-liquid separation device 6 include a centrifuge and a rotary vacuum filter. This solid-liquid separator 6 separates and recovers the sodium bicarbonate crystals, and the filtrate is partially blown out of the system and the remainder from the reverse osmosis membrane type concentrator 2 as shown in FIG. The non-permeated water (membrane concentrated water) is mixed and supplied to the heat recovery device 3.

  Table 1 shows an example of the composition of groundwater from which sodium hydrogen carbonate was recovered by the recovery device 1 of this embodiment.

この表１には、逆浸透膜式濃縮装置２によって膜濃縮した原水（膜濃縮水）の組成も併せて示している。

Table 1 also shows the composition of the raw water (membrane concentrated water) concentrated by the reverse osmosis membrane type concentrator 2.

  The raw water having the composition shown in Table 1 concentrated in the membrane by the reverse osmosis membrane type concentration device 2 was concentrated by evaporation using the evaporation type concentration device 4.

The flow rate of the groundwater of the components shown in Table 1 was 26 m ³ / h, and the flow rate of the circulating liquid from the solid-liquid separator 6 was 3 m ³ / h. The evaporation capacity of the evaporation type concentration device 4 was 23 t / h, and the supplied raw water was concentrated about 6 times. In the second effect of the evaporative concentration apparatus, 640 kg (7.6 kmol / h) of sodium hydrogen carbonate crystals are produced, and 3.7 t / h of concentrated raw water is taken out.

  Inside the evaporative concentrator 4, carbon dioxide gas is generated from the raw water to be concentrated and is discharged from the outlet of the vacuum pump 29 described above. The amount of this carbon dioxide gas was 56 kg / h.

さらにこの結晶を分離した濃縮原水から乾燥重量が４０５ｋｇ／ｈ（４．８ｋｍｏｌ／ｈ）の炭酸水素ナトリウムの結晶物が得られた。

Furthermore, a crystal of sodium hydrogen carbonate having a dry weight of 405 kg / h (4.8 kmol / h) was obtained from the concentrated raw water from which the crystals were separated.

  The groundwater contains the following soda components, as shown in Table 1 above.

HCO ₃ : 6,300 mg / L, 6.3 / 61 = 0.1 mol / L
CO ₃ : 1300 mg / L, 1.3 / 60 = 0.022 mol / L
Total, 0.122 mol / L, ie 0.122 kmol / m ³
Since the raw water flow rate is 140 m ³ / h as shown in Table 1,
Since 0.122 kmol * 140 m ³ = 17.1 kmol, the yield is (7.6 + 4.8) /17.1=73%.

  According to this embodiment, sodium hydrogen carbonate can be recovered with a yield of 70% or more.

  In the above-described embodiment, the groundwater is described as applied to the accompanying water generated when collecting coal-bed methane gas. However, the groundwater can be similarly applied to other groundwater containing sodium carbonate, sodium bicarbonate, and sodium chloride. It is.

  Although the evaporative concentration apparatus is configured to precipitate crystals with the second effect, a separate evaporative concentration type crystallizer may be provided in the subsequent stage so that crystals are not generated inside the evaporative concentration apparatus.

  Although the carbon dioxide absorption crystallization apparatus 5 is a jacket type cooling system using a chiller, it may be 35 ° C. to 40 ° C. that can be realized in the case of a normal cooling tower, and the cooling system is not limited to the jacket system. You may use the structure which has arrange | positioned the cooling pipe inside the can, and another crystallizer.

  In the above-described embodiment, the carbon dioxide gas generated in the evaporation type concentrator is introduced into the carbon dioxide absorption crystallizer and brought into contact with the concentrated raw water. However, as another embodiment of the present invention, the reverse osmosis membrane type concentrator is used. The carbon dioxide contained in the permeated water separated by the apparatus may be taken out by a vacuum deaerator, etc., and the carbon dioxide may be introduced into the carbon dioxide absorption crystallizer and brought into contact with the concentrated raw water, or You may introduce | transduce into the carbon dioxide absorption crystallizer both the carbon dioxide gas generated with the evaporation type | formula concentration apparatus and the carbon dioxide gas taken out from the permeated water.

2 Reverse Osmosis Membrane Concentrator 3 Heat Recovery Device 4 Evaporation Concentrator 5 Carbon Dioxide Absorption Crystallizer 6 Solid-Liquid Separator 7 First Effect Evaporator 8 Second Effect Evaporator 19 Crystal Can

Claims (7)

An apparatus for recovering sodium bicarbonate from ground water containing at least sodium carbonate, sodium bicarbonate and sodium chloride,
An evaporative concentrator for concentrating the groundwater;
A carbon dioxide absorption crystallization apparatus for bringing concentrated hydrogen water concentrated by the evaporation type concentration apparatus into contact with carbon dioxide and precipitating sodium hydrogen carbonate crystals;
Introducing carbon dioxide gas generated in the evaporative concentration apparatus into the concentrated groundwater in the carbon dioxide absorption crystallization apparatus,
A sodium hydrogen carbonate recovery device. A reverse osmosis membrane type concentrating device for separating the groundwater before concentration supplied to the evaporation type concentrating device into permeated water and membrane concentrated water;
The membrane concentrated water separated by the reverse osmosis membrane type concentrator is supplied to the evaporative concentrator as groundwater before concentration.
The sodium hydrogen carbonate recovery device according to claim 1. An apparatus for recovering sodium bicarbonate from ground water containing at least sodium carbonate, sodium bicarbonate and sodium chloride,
An evaporative concentrator for concentrating the groundwater;
A carbon dioxide absorption crystallizer for bringing sodium hydrogen carbonate crystals into contact with the carbon dioxide gas by bringing the concentrated groundwater concentrated by the evaporative concentration device into contact with the carbon dioxide gas;
A reverse osmosis membrane type concentrating device that separates the groundwater before concentration supplied to the evaporation type concentrating device into permeated water and membrane concentrated water;
The carbon dioxide contained in the permeated water separated by the reverse osmosis membrane type concentrator is taken out and introduced into the concentrated groundwater in the carbon dioxide absorption crystallization device, while being separated by the reverse osmosis membrane type concentrator. Supplying the concentrated membrane water to the evaporative concentrator as groundwater before concentration,
A sodium hydrogen carbonate recovery device. A heat recovery device that preheats the groundwater before concentration supplied to the evaporative concentration device by heat of the concentrated groundwater concentrated by the evaporative concentration device;
The sodium hydrogen carbonate recovery device according to any one of claims 1 to 3. The groundwater is associated water discharged from the coal bed together with carbon dioxide,
The sodium hydrogen carbonate recovery device according to any one of claims 1 to 4. A method for recovering the sodium bicarbonate from ground water containing at least sodium carbonate, sodium bicarbonate and sodium chloride,
Evaporating and concentrating the groundwater;
And concentrating the groundwater evaporated and concentrated in the above step with carbon dioxide gas to precipitate sodium hydrogencarbonate crystals,
In the step of precipitating, carbon dioxide gas generated in the step of evaporating and concentrating is introduced into the concentrated groundwater.
A method for recovering sodium hydrogen carbonate, characterized in that A method for recovering the sodium bicarbonate from ground water containing at least sodium carbonate, sodium bicarbonate and sodium chloride,
Separating the groundwater into permeated water and membrane concentrated water by a reverse osmosis membrane;
Evaporating and concentrating the separated membrane concentrated water into concentrated groundwater;
Bringing the concentrated groundwater evaporated and concentrated into contact with carbon dioxide gas to precipitate sodium hydrogen carbonate crystals,
In the precipitating step, the carbon dioxide gas contained in the permeated water separated by the reverse osmosis membrane is taken out and introduced into the concentrated groundwater.
A method for recovering sodium hydrogen carbonate, characterized in that

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