JP4377104B2 - Desalination equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a desalting apparatus using electrodialysis. More specifically, a desalinator for producing industrial chemicals such as a dealkalized water glass aqueous solution useful as a material for ground injection, a desalinator for removing ions that cause environmental pollution from waste incineration ash cleaning liquid, etc. The present invention relates to a desalting apparatus used in various applications.
[0002]
[Prior art]
In civil engineering work, a chemical injection method is generally used to improve the ground by injecting a ground improvement material from the outside to the ground that may be collapsed by excavation or the like, or the ground that is difficult to excavate by spring water or the like. Various ground improvement materials are currently used, but recently, the strength of the solidified product by injection is high and its durability is excellent, and the injection time is one solution and the gel time can be easily adjusted for handling. Since it is convenient, a silica sol-based ground improvement injection material mainly composed of water glass is often used.
[0003]
By the way, this silica sol-based ground improvement injecting material contains a large amount of alkali metal salt, which causes a decrease in the strength of the resulting solidified body, or the alkali or salt from the solidified body over time. There is a problem that the solidified body shrinks due to free or deviating, and its durability is lowered. In order to improve such defects, a method of removing alkali content from water glass by ion exchange resin method is adopted. (JP-A-11-279552). However, the dealkalization treatment by the ion exchange resin method requires regeneration of the resin, so long-term dealkalization treatment is impossible. ₂ Since water glass having a high concentration gels in the vicinity of the resin, the conditions for use are restricted.
[0004]
Therefore, recently, a method of dealkalizing water glass with an ion exchange membrane electrodialyzer has been adopted (Japanese Patent Laid-Open No. 11-61124). In this method, an electrodialysis tank, a pair of anodes and cathodes respectively arranged on opposite end faces inside the tank, and an anion exchange membrane on the most anode side between these positive and negative electrodes, Consists of cation and anion exchange membranes arranged alternately and so as to form a plurality of compartments where the cation exchange membranes are located, and among these compartments, the compartments where the anode and the cathode are located In addition, water glass and water are alternately filled in the other compartments, and an electric current is passed between the positive and negative electrodes, so that Na in the water glass is filled. ⁺ Ions are permeated and released through the membrane into the water filled in the adjacent compartment on one side through the cation exchange membrane, and OH ⁻ Ions are released through the membrane through the anion-exchange membrane into the water on the other side, and the water glass is dealkalized to obtain dealkalized water glass.
[0005]
[Problems to be solved by the invention]
However, when the above-mentioned method was carried out continuously for a long period of time, as the dialysis time passed, deposits mainly composed of silicate adhered to the membrane and flow path of the desalination chamber, and the membrane resistance increased or the feed of the raw material was increased. It has been found that the dealkalization ability decreases with the passage of dialysis time due to difficulty, and if the operation is continued as it is, the membrane deteriorates and becomes inoperable. It has been found that the flow path can be recovered by flushing or washing, and a deteriorated film can be regenerated by a process such as alkali washing (Japanese Patent Application No. 2001-025323). The regeneration process is difficult to perform on site, and the desalinator manufacturer's service personnel remove the deteriorated membrane (usually in the form of a module called stack) and replace it with a new membrane (stack). ) Must be taken back to the desalinator manufacturer. The occurrence of such emergency maintenance work affects the product production plan. Further, frequent periodic inspections to avoid an emergency stop of the apparatus are problematic in terms of cost.
[0006]
Such problems are not limited to the case of desalinized water glass production, but when desalting a desalted solution containing ions that are sources of precipitates (scale) such as silicate ions, calcium ions, and magnesium ions. It is also a common problem. For example, the present inventor has been studying the removal of chlorine ions from the washing water of garbage incineration ash using a desalting apparatus similar to the above, but since the washing liquid contains calcium ions, We have experienced similar problems due to the generation of precipitates (scales) derived from ions.
[0007]
Accordingly, the present invention provides a desalination apparatus that can monitor the deterioration state of the membrane and the environment of the desalting room and automatically perform a regeneration process in order to prevent the occurrence of the above problems. Objective.
[0008]
In addition, in the above Japanese Patent Application No. 2001-025323, when producing a dealkalized water glass by desalting (dealkalizing) water glass by an ion exchange membrane electrodialysis method, the inside of the ion exchange membrane and its surface during electrodialysis are disclosed. The scale can be removed by supplying a high-concentration alkaline solution to the desalting chamber and the concentrating chamber when the scale containing silicate as a main component adheres to the desalination efficiency and the desalting efficiency is lowered. It is described together with an example (Example 1) that desalting efficiency is recovered by performing the above. That is, in Example 1, an electrodialysis apparatus (TS2-10 type) manufactured by Tokuyama Corporation was used, and a JIS standard No. 3 water glass aqueous solution was diluted with water to 4.6 wt% (Na ₂ A water glass aqueous solution adjusted to an O concentration of 1.45 wt% was supplied to the desalting chamber, and a sodium hydroxide aqueous solution (0.5 mol / l) was supplied to the concentration chamber to demineralize the raw water glass of 2 (l). However, Na ₂ The time required for the treatment until the O concentration became 0.49 wt% was 52 minutes, and the average current density at that time was 1.4 (A / dm). ² However, when the same raw material was repeatedly energized for 250 hours, the same raw material was desalted with water glass aqueous solution 2 (l). ₂ The time required for the treatment until the O concentration became 0.49 wt% was 104 minutes, and the average current density at that time was 0.7 (A / dm). ² ) And the desalting efficiency was reduced, but when the sodium salt aqueous solution of 0.5 (mol / l) was circulated and washed in the desalting chamber, the concentrating chamber and the pipes leading to these for 4 hours, the desalting efficiency was It has been shown to recover.
[0009]
[Means for Solving the Problems]
The present inventors have intensively studied to solve the above problems. As a result, the degradation status of the film is At the ends of the unit consisting of a pair of desalting chambers and salt concentration chambers adjacent to each other Voltage between diaphragms Or the voltage used as an indicator It can be grasped by monitoring the flow rate or pressure of the desalted liquid supplied to the desalting chamber, the electrical conductivity of the desalted liquid, and the degradation status thus grasped in a specific range. In this case, the indoor environment including the membrane can be restored to the initial state by flowing a cleaning solution such as an alkaline aqueous solution into the desalting chamber, and the frequency of membrane (or stack) replacement is greatly reduced. The present inventors have found that this can be done and have completed the present invention.
[0010]
The present invention includes substances (for example, silicate ions, calcium ions, etc.) that generate precipitates (scale) during electrodialysis, such as waste water (waste incineration ash cleaning liquid) when water glass aqueous solution or incineration ash is washed with water. A desalting apparatus that can be suitably used for desalting a desalinated liquid, and having the following structure.
(A) Desalination chamber in which anion exchange membranes and cation exchange membranes are alternately arranged between an anode and a cathode, and the anode side is partitioned by an anion exchange membrane and the cathode side is partitioned by a cation exchange membrane. And an electrodialysis tank in which a salt concentration chamber in which the anode side is partitioned by a cation exchange membrane and the cathode side is partitioned by an anion exchange membrane, and (B) for supplying a desalted solution to the desalting chamber A pipe for supplying a desalted liquid, (C) a pipe for extracting a desalted liquid for extracting the desalted liquid desalted from the desalting chamber, and (D) a salt absorbing liquid in the salt concentrating chamber. A salt removal apparatus comprising: a salt absorption liquid supply pipe for supply; and (E) a concentrate extraction pipe for extracting a concentrate that is a salt absorption liquid in which salt is concentrated from the salt concentration chamber. ,
(1) A cleaning liquid supply pipe for supplying a cleaning liquid to the desalting chamber,
(2) Supply liquid switching means for switching the liquid supplied to the desalting chamber to either the desalted liquid or the cleaning liquid,
(3) a cleaning liquid extraction pipe for extracting the cleaning liquid from the desalting chamber;
(4) Extraction flow path switching means for switching the flow path of the liquid extracted from the desalting liquid to a desalting liquid extraction pipe or a cleaning liquid extraction pipe,
(5) A desalted liquid flow rate detector for detecting the flow rate of the desalted liquid supplied to the desalting chamber, and a desalted liquid pressure for detecting the pressure of the desalted liquid supplied to the desalting chamber. A detector, a desalting solution electrical conductivity detector for detecting the electrical conductivity of the desalting solution flowing through the desalting solution extraction pipe, and a pair of adjacent desalting chambers disposed in the electrolytic cell; And a voltage detector for detecting a voltage between the diaphragms at both ends of the unit comprising the salt concentration chamber or a voltage as an index thereof, and
(6) Based on the detection value of the detector When the deterioration condition of the anion exchange membrane, cation exchange membrane, and demineralization room environment is monitored and a predetermined deterioration condition is reached within the range of the recovery condition that can be recovered by circulating cleaning liquid Operate the supply liquid switching means and the extraction flow path switching means. In order to circulate the cleaning liquid in the desalination chamber Control means for controlling the switching of the supply liquid supplied to the desalting chamber and the flow path of the liquid withdrawn from the desalting chamber
It is a desalination apparatus characterized by having.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The desalting apparatus of the present invention is similar to the conventional desalting apparatus in that (A) an anion exchange membrane (hereinafter also referred to as AE membrane) and a cation exchange membrane (hereinafter CE) are provided between the anode and the cathode. A salt concentration chamber in which the anode side is partitioned by an AE membrane and the cathode side is partitioned by a CE membrane, and the anode side is partitioned by a CE membrane and the cathode side is partitioned by an AE membrane. An electrodialysis tank in which is formed, (B) a desalting solution supply pipe for supplying a desalting solution to the desalting chamber, and (C) desalting desalted from the desalting chamber A pipe for extracting a desalted liquid for extracting the liquid; (D) a pipe for supplying a salt absorbing liquid to supply the salt absorbing liquid to the salt concentrating chamber; and (E) a salt being concentrated from the salt concentrating chamber. And a concentrate extraction pipe for extracting the concentrate that is the salt absorbing solution.
[0012]
Here, the desalination chamber refers to an anion derived from the salt permeating through the AE membrane on the anode side when electrodialysis is performed by supplying a desalted solution containing salt in the form of ions to the chamber. And a cation derived from a salt permeates through the CE membrane on the cathode side and diffuses, resulting in a chamber in which the salt concentration in the chamber decreases. The salt concentrating chamber is supplied from the AE membrane and the CE membrane to the adjacent desalting chamber when a salt absorbing solution made of water or an aqueous electrolyte solution is supplied to the chamber and electrodialysis is performed in the same manner. It means a chamber in which salt-derived anions and cations permeate through each membrane and as a result the salt concentration in the chamber increases. For example, by supplying a water glass aqueous solution as a desalted solution to the desalting chamber and supplying a salt absorbing solution made of an aqueous electrolyte solution such as an alkali hydroxide aqueous solution to the salt concentrating chamber and performing electrodialysis, Na present in the supplied water glass ⁺ Alkali metal ions such as ions permeate the CE membrane, diffuse through the CE membrane to the adjacent salt concentration chamber, and are also present in the water glass. ⁻ Ions permeate the AE membrane and diffuse to the adjacent salt concentration chamber through the AE membrane, and as a result, a water glass having a reduced alkali concentration in the water glass can be obtained as a desalting solution. At this time, in the concentrating chamber, Na diffused from the adjacent desalting chambers. ⁺ Alkali metal ions such as ions and OH ⁻ Ions are confined, and an aqueous alkali hydroxide solution having an increased concentration is obtained as a concentrate.
[0013]
In addition, what is used with the conventional electrodialysis apparatus is also used without a restriction | limiting also about the electrode and each ion exchange membrane which are members required for comprising the above apparatuses. That is, as the anode and cathode used in the electrodialysis tank, electrodes employed in the electrochemical industry such as water electrolysis and salt electrolysis are used without limitation. For example, nickel, iron, lead, titanium, platinum, graphite and the like are suitably used as the anode material, and nickel, iron, stainless steel, platinum, titanium and the like are suitably used as the cathode material.
[0014]
The anion exchange membrane (AE membrane) is not particularly limited as long as it is a membrane having anion selective permeability made of a resin having anion exchange groups bonded thereto, and a known anion exchange membrane can be used. As the anion exchange group, a functional group that can be positively charged in an aqueous solution can be used without any particular limitation. Specific examples include a primary to tertiary amino group, a pyridyl group, a quaternary ammonium base, a quaternary pyridinium base, and a mixture of these ion exchange groups. As AE membrane, it can be used without distinction of polymerization type, condensation type, homogeneous type, heterogeneous type, etc. Furthermore, the presence or absence of a reinforcing material used for reinforcement, the material of the resin to which the ion exchange group is bonded (Normally, a hydrocarbon-based resin or a fluorine-based resin is used) is not particularly limited.
[0015]
The cation exchange membrane (CE membrane) is not particularly limited as long as it is a membrane having a selective cation permeability made of a resin bonded with a cation exchange group, and a known cation exchange membrane can be used. As the cation exchange group, a functional group that can be negatively charged in an aqueous solution can be used without particular limitation. Specific examples include sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, sulfate ester groups, phosphate ester groups, and those in which these ion exchange groups are mixed. As CE membrane, it can be used without distinction of polymerization type, condensation type, homogeneous type, non-homogeneous type, etc. Furthermore, the presence or absence of a reinforcing material used for reinforcement, the material of the resin to which the ion exchange group is bonded (Normally, a hydrocarbon-based resin or a fluorine-based resin is used) is not particularly limited.
[0016]
In addition, the desalination apparatus of the present invention monitors (1) the state of deterioration of the membrane and the environment of the desalting chamber during desalting, and (1) supplies cleaning liquid to the desalting chamber in order to automatically perform the regeneration treatment. (2) Supply liquid switching means for switching the liquid supplied to the desalting chamber to either the desalted liquid or the cleaning liquid, and (3) extracting the cleaning liquid for extracting the cleaning liquid from the desalting chamber. (4) Extraction flow path switching means for switching the flow path of the liquid extracted from the desalting liquid to a desalting liquid extraction pipe or a cleaning liquid extraction pipe, (5) Supply to the desalting chamber A flow rate detector for detecting the flow rate of the desalted liquid, a pressure sensor for detecting the pressure of the desalted solution supplied to the desalting chamber, and a desalted solution extraction A desalinating liquid conductivity detector for detecting the electrical conductivity of the desalting liquid flowing through the pipe for use, and each other disposed in the electrolytic cell Voltage detector for detecting a voltage or voltage to be the index of between a pair of diaphragm at both ends of the unit comprising the desalting and salt concentration compartments in contact, and (6) based on a detection value of the detector When the deterioration condition of the anion exchange membrane, cation exchange membrane, and demineralization room environment is monitored and a predetermined deterioration condition is reached within the range of the recovery condition that can be recovered by circulating cleaning liquid Operate the supply liquid switching means and the extraction flow path switching means. In order to circulate the cleaning liquid in the desalination chamber Control means for controlling the switching of the supply liquid supplied to the desalting chamber and the flow path of the liquid withdrawn from the desalting chamber is provided.
[0017]
In the desalination apparatus of the present invention, the deterioration state of the membrane and the environment of the desalting chamber is monitored by the above detector, and the cleaning liquid is supplied into the desalting chamber, preferably within the range of the recoverable degradation state by circulating it. It is possible to restore the environment in the membrane and the desalting chamber by automatically operating the control means when a predetermined deterioration state is reached and switching the flow path to distribute the cleaning liquid in the desalting chamber. It has become. The set value for operating the control means is the relationship between the detection knowledge detected by each detector according to the type of desalted liquid and the desalting conditions and the deterioration status, and further the deterioration status that can be recovered by the cleaning operation. It is determined appropriately by checking the above. Further, the cleaning liquid conditions (the flow rate of the cleaning liquid, the circulation time, and the cleaning liquid temperature) can also be determined by conducting a preliminary experiment according to the deterioration state and the type of the cleaning liquid used. After completion of the cleaning process, the flow path can be switched again to resume desalting. At this time, the flow path can be switched automatically or manually. In addition, what kind of washing | cleaning liquid should just select and use suitably the liquid which can melt | dissolve a scale by the kind of scale (in other words, the kind of to-be-desalted liquid). For example, when desalting a water glass aqueous solution, an alkaline aqueous solution such as a sodium hydroxide aqueous solution can be used, and a hydrochloric acid aqueous solution when desalting the waste incineration ash cleaning liquid (waste liquid when the waste incineration ash is washed with water). An acid aqueous solution such as can be used.
Hereinafter, the desalination apparatus of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram of a representative desalination apparatus 100 of the present invention. The desalting apparatus 100 basically includes an electrodialysis tank 110, a desalted liquid supply pipe 120 connected to the electrodialysis tank 110, a desalted liquid extraction pipe 121, a salt absorbing liquid supply pipe 130, and a concentration. The liquid extraction pipe 131, the cleaning liquid supply pipe 140, and the cleaning liquid extraction pipe 141 are configured. The desalted liquid supply pipe 120 can be supplied with the desalted liquid from the desalted liquid tank 301 using the pump 310 a, and is extracted through the desalted liquid extracting pipe 121. The desalted liquid is circulated to the desalted liquid tank 301. Similarly, salt absorption liquid can be supplied from the salt absorption liquid tank 302 to the salt absorption liquid supply pipe 130 using the pump 310b. The concentrated liquid extracted through the concentrated liquid extraction pipe 131 is The salt absorbent tank 302 is circulated. Further, the cleaning liquid supply pipe 140 can supply the cleaning liquid to the cleaning liquid tank 303 using the pump 310 c, and the cleaning liquid extracted through the cleaning liquid extraction pipe 141 is circulated to the cleaning liquid tank 303. It has become.
As shown in FIG. 2, the electrodialyzer 110 is a modular stack in which two or more units 210 each including an adjacent desalting chamber 211 and a salt concentration chamber 212 are connected between an anode 111 and a cathode 112. A plurality of 200 are provided. (In FIG. 1, the structure in the stack is omitted, and only the flow of the liquid is shown.) By using such a stack, not only the piping can be simplified, but also, for example, the exchange of the ion exchange membrane can be performed in the stack. The maintenance of the apparatus becomes easy. The space on the anode side from the stack including the anode 111 is the anode chamber 111R, the space on the cathode side from the stack including the cathode 112 is the cathode chamber 112R, and an electrode solution made of an electrolyte aqueous solution is contained in each chamber. The tank 304 can be supplied and circulated using a pump 310d.
In addition, as shown in FIG. 2, the stack 200 has two or more units of the AE film 230 and the CE film 240 through a chamber frame 220 having a notch for forming each chamber in the center. In this way, the module is a so-called filter press type structure that is alternately and repeatedly arranged and then fixed from both ends, and in each chamber in the stack, the spacer 250 for securing the flow path and the liquid are evenly distributed. A flow distribution plate (not shown) is provided. Further, the chamber frame 220 is provided with notches for forming a desalting chamber liquid supply path 221, a desalting chamber liquid outflow path 222, a salt concentration chamber liquid supply path 223, and a salt concentration chamber liquid outflow path 224. ing. In addition, the shape of the spacer or flow distribution plate is not particularly limited, but it has an effect of preventing the generation of precipitates, and has a structure that can be easily removed even if precipitates are generated, for example, a tunnel type structure. It is preferred to use.
[0018]
A desalting chamber liquid supply path 221 leading to each desalting chamber 211 in each stack 200 is connected to a liquid outflow end of a desalted liquid supply pipe 120, and the desalted liquid supply pipe 120. The liquid outflow end side is also used as the liquid outflow end side of the cleaning liquid supply pipe 140, and this desalted liquid supply / cleaning liquid supply pipe 150 is once collected in the upstream portion to be supplied with the demineralized liquid supply / cleaning liquid. After the supply / main pipe 160 is formed, it is branched into dedicated pipes for the desalinated liquid supply pipe 120 and the cleaning liquid supply pipe 140. Further, similarly, a liquid outflow end of the branch pipe 130b branched from the main pipe 130a of the salt absorbing liquid supply pipe 130 is connected to the salt concentration chamber liquid supply path 223 leading to each salt concentration room 212 in each stack 200. The salt concentration chamber liquid outflow passages 224 leading to the salt concentration chambers 212 are connected to the liquid outflow ends of the branch pipes 131b of the concentrate extraction pipe 131, and the branch pipes 131b are collected at the downstream portions thereof. Main tube 131a is formed.
In addition, a valve 170a installed in a dedicated pipe portion of the desalted liquid supply pipe 120 upstream of the desalted liquid supply / cleaning liquid supply main pipe 160 and the desalted liquid supply / cleaning liquid supply Supply liquid switching means comprising a valve (valve) 170b installed in a dedicated pipe portion of the cleaning liquid supply pipe 140 upstream of the main pipe 160 is installed. Further, the desalting chamber liquid outflow passage 222 of each desalting chamber in the stack 200 is connected to the liquid inflow end of the desalinating solution extraction piping 121, and the desalting solution extraction piping 121 liquid is connected thereto. The inflow end side is also used as the liquid inflow end side of the cleaning liquid extraction pipe 141, and this desalting liquid extraction / cleaning liquid extraction pipe 151 is once collected in the downstream portion to remove the desalting liquid extraction / cleaning liquid After forming the main outlet pipe 161, it branches off to the dedicated pipes of the desalinating liquid extraction pipe 121 and the cleaning liquid extraction pipe 141. Then, a valve (valve) 171a installed in a dedicated pipe portion of the desalting liquid extraction pipe 121 downstream of the desalting liquid extraction / cleaning liquid extraction main pipe 161 and the desalting liquid extraction / cleaning liquid extraction Extraction flow path switching means comprising a valve (valve) 171 b installed in a dedicated pipe portion of the cleaning liquid extraction pipe 141 downstream from the output / main pipe 161 is provided. In addition, although the aspect which consists of two valves each as supply liquid switching means and extraction flow path switching means was shown in FIG. 1, if it is a means which can switch a flow path, other means, for example, a three-way valve, It is of course possible to use a four-way valve (in this case a return line is required). These switching means can be operated by electric power or air pressure, and are operated based on a signal transmitted from the control means 190 described later.
[0019]
In the desalting apparatus 100 of the present invention, the desalted liquid flow rate detector 181 comprising a flow meter for detecting the flow rate of the desalted liquid is provided in the dedicated pipe portion of the desalted liquid supply / cleaning liquid supply main pipe 160 and A desalted liquid pressure detector 182 comprising a pressure gauge for detecting the pressure of the desalted liquid is installed, and the electric conductivity of the desalted liquid is provided in the main portion 161 of the desalted liquid withdrawing / washing liquid outlet. A demineralized liquid electrical conductivity detector 183 is installed for detecting water. Further, a voltage detector 184 for detecting the voltage between the ion exchange membranes at both ends of each stack is installed. The voltage detector detects the voltage between the ion exchange membranes at both ends of the stack, and this voltage is also an indicator of the voltage at the ion exchange membranes at both ends of each unit between the stacks. Of course, the voltage of each unit may be measured, but it is preferable to install a voltage detector for each stack because the number of detectors can be reduced and the detection sensitivity can be maintained at an effective level or higher. When precipitation of scale occurs during the desalting operation and the amount of precipitation increases, the flow path in the desalting chamber or in the vicinity of the desalting chamber liquid supply path narrows, and the flow rate of the desalting liquid decreases or the desalting liquid Or the pressure will rise. Moreover, when scale adheres to the ion exchange membrane, the membrane resistance increases and the desalting efficiency decreases, so the voltage between the ion exchange membranes increases, and the time for reducing the electrical conductivity of the desalting solution increases. The detection value detected by each detector is transmitted from the transmitter attached to each detector to the control means through the receiver attached to the control means 190 of (6). The control means 190 performs the operation and control of the desalinating apparatus 100, and when the transmitted detection value matches or exceeds the preset detection, the supply liquid is supplied immediately or in a preset procedure. A signal for operating the switching means and the extraction flow path switching means is transmitted, and each switching means operates to switch the supply liquid supplied to the desalting chamber and the flow path of the liquid extracted from the desalting chamber. The ion exchange membrane is automatically regenerated and the desalting operation is resumed. At this time, the operation and stop of each device such as a pump are also controlled.
[0020]
【The invention's effect】
According to the apparatus of the present invention, a substance (for example, silicate ion or calcium ion) that generates precipitates (scale) during electrodialysis, such as a waste liquid (waste incineration ash washing liquid) when water glass aqueous solution or incineration ash is washed with water. In the case of desalting the desalted solution containing the above, etc., the scale can be removed by automatically performing the washing operation before the adverse effect due to the scale deposition becomes unrecoverable. Therefore, the apparatus can be used stably for a long period of time without urgently stopping the apparatus. In addition, the period of the regular inspection can be extended, and the cost required for maintenance can be reduced.
[0021]
[Brief description of the drawings]
FIG. 1 is a schematic view of a desalting apparatus according to the present invention.
FIG. 2 is a schematic view of a stack used in the desalination apparatus of the present invention.
[Explanation of symbols]
100: Demineralizer
110: Electrodialysis tank
111: Anode
112: Cathode
111R: Anode chamber
112R: Cathode chamber
120: Pipe for supplying desalted liquid
121: Pipe for extracting desalted liquid
130: Pipe for supplying salt absorption liquid
130a: Main pipe of salt absorption liquid supply pipe
130b: Branch pipe of salt absorption liquid supply pipe
131: Pipe for extracting concentrated liquid
131a: Main pipe for extracting concentrated liquid
131b: Branch pipe for extracting concentrated liquid
140: piping for supplying cleaning liquid
141: and piping for extracting cleaning liquid
150: piping for supplying desalinated liquid and supplying cleaning liquid
151: Deionized solution supply / cleaning solution extraction piping
160: Desalted liquid supply / cleaning liquid supply main pipe
161: Desalinated liquid supply / cleaning liquid extraction combined use main pipe
170a, b: Valve (supply liquid switching means)
171a, b: Valve (extraction flow path switching means)
181: Demineralized liquid flow rate detector
182: Desalinated liquid pressure detector
183: Desalinated liquid electrical conductivity detector
184: Voltage detector
190: Control means
200: Stack
210: Unit
211: Desalination room
212: Salt concentration chamber
220: Room frame
221: Desalination chamber liquid supply path
222: Desalination chamber liquid outflow passage
223: Salt concentration chamber liquid supply path
224: Salt concentration chamber liquid outflow passage
230: AE film
240: CE film
250: Spacer
301: Desalinated liquid tank
302: Salt absorption liquid tank
303: Cleaning liquid tank
304: Electrode solution tank
310a to d: Pump

Claims (6)

(A) An anion exchange membrane and a cation exchange membrane are alternately arranged between an anode and a cathode, and a desalting chamber in which the anode side is partitioned by an anion exchange membrane and the cathode side is partitioned by a cation exchange membrane, and An electrodialysis tank in which a salt concentration chamber having an anode side partitioned by a cation exchange membrane and a cathode side partitioned by an anion exchange membrane is formed; and (B) a detoxification for supplying a desalted solution to the desalting chamber. A salt solution supply pipe, (C) a desalted solution extraction pipe for extracting the desalted solution desalted from the desalting chamber, and (D) a salt absorbing solution is supplied to the salt concentration chamber. A salt-absorbing solution supply pipe and (E) a salt-extracting pipe for extracting a concentrate that is a salt-absorbing solution in which salt is concentrated from the salt concentration chamber,
(1) A cleaning liquid supply pipe for supplying a cleaning liquid to the desalting chamber, (2) a supply liquid switching means for switching the liquid supplied to the desalting chamber to a desalted liquid or a cleaning liquid, (3) (4) Extraction flow for switching the flow path of the liquid extracted from the desalting liquid to the desalting liquid extraction pipe or the cleaning liquid extraction pipe. A path switching means, (5) a flow rate detector for detecting the flow rate of the desalted liquid supplied to the desalting chamber, and a flow rate detector for detecting the pressure of the desalted liquid supplied to the desalting chamber. A desalting solution pressure detector, a desalting solution electrical conductivity detector for detecting the electrical conductivity of the desalting solution flowing in the desalting solution extraction pipe, and a set adjacent to each other disposed in the electrolytic cell For detecting the voltage between the diaphragms at both ends of the unit consisting of the desalting chamber and the salt concentration chamber of the water or the voltage serving as an index thereof Intellectual instrument, and (6) the detector based on the detected value anion-exchange membrane, to monitor the deterioration condition of the cation exchange membrane and desalination indoor environment, the range of recoverable deterioration state by circulating the washing liquid The supply liquid switching means and the extraction flow path switching means are operated when a predetermined deterioration state is reached in order to switch the supply liquid supplied to the desalting chamber so that the cleaning liquid flows in the desalting chamber. A desalinator comprising control means for controlling and controlling a flow path of a liquid extracted from the desalting chamber. The electrodialysis tank has a plurality of units composed of an adjacent desalination chamber and a salt concentration chamber between the anode and the cathode, and the desalination chamber liquid supply path in the electrodialysis tank has a cover. The liquid outflow end of the desalted liquid supply pipe is connected, and the liquid outflow end side of the desalted liquid supply pipe is also used as the liquid outflow end side of the cleaning liquid supply pipe. The liquid supply / cleaning liquid supply pipe is branched into dedicated pipes for the desalted liquid supply and the cleaning liquid supply pipe in the upstream portion, while the desalting chamber liquid discharge path in the electrodialysis tank has The liquid inflow end of the desalting liquid extraction pipe is connected, and the liquid inflow end side of the desalting liquid extraction pipe is also used as the liquid inflow end side of the cleaning liquid extraction pipe. The pipe for both the liquid extraction and cleaning liquid extraction is branched into a dedicated pipe for the desalination chamber extraction pipe and the cleaning liquid extraction pipe in the downstream part. Desalination apparatus according to claim 1 that. A plurality of modularized stacks in which two or more of the above units are connected in an electrodialysis tank, and a desalted liquid supply / cleaning liquid supply pipe connected to a desalination chamber liquid supply path in each stack Are collected once to form the main pipe for supplying the desalted liquid and cleaning liquid, and then branched to the dedicated pipes for supplying the desalted liquid and the cleaning liquid supplying pipe, while the desalting in each stack The desalting liquid extraction / cleaning liquid extraction piping connected to the chamber liquid discharge passage is once collected to form a desalting liquid extraction / cleaning liquid extraction main pipe, and then the desalting chamber extraction piping and cleaning liquid extraction The demineralizer according to claim 2, wherein the demineralizer is branched to each dedicated pipe of the outgoing pipe. The supply liquid switching means includes a valve installed in a dedicated pipe portion of the demineralized liquid supply pipe upstream of the demineralized liquid supply / cleaning liquid supply main pipe and a demineralized liquid supply / cleaning liquid supply main pipe. And a valve installed in a dedicated pipe part of the upstream of the cleaning liquid supply pipe, and the extraction flow path switching means is downstream of the desalinating liquid extraction / cleaning liquid extraction main pipe. And a valve installed in a dedicated pipe portion of the cleaning liquid extraction pipe downstream of the desalinating liquid extraction / cleaning liquid extraction main pipe. 3. The desalinating apparatus according to 3. The desalinating apparatus according to claim 3 or 4, wherein the voltage detector detects a voltage between ion exchange membranes at both ends of at least one stack disposed in the electrodialysis tank. A method for producing a desalted solution, wherein the desalted solution is desalted using the desalting apparatus according to any one of claims 1 to 5.

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