JP5101322B2 - Pure water production method and apparatus - Google Patents

Description

  The present invention relates to a pure water production method and apparatus for producing pure water by passing raw water through a reverse osmosis membrane separation device.

  Conventionally, as a pure water production apparatus for producing pure water using a reverse osmosis membrane separation apparatus (hereinafter referred to as RO apparatus), as shown in FIG. It is preheated to 30 ° C. to 35 ° C. by passing through the heat recovery heat exchanger 202, then heated to 40 ° C. to 45 ° C. through the heating heat exchanger 203, and is supplied to the reverse osmosis membrane by the supply pump 204. It is supplied to the RO device 205 that performs the separation process of pure water, and the treated water treated by the RO device 205 is degassed by the deaeration device 206 and then passed through the heat recovery heat exchanger 202 to recover the heat. Known is treated water at 30 ° C. to 35 ° C. and ion exchange equipment 207 is used for ion exchange to produce treated water (pure water) (see, for example, Patent Document 1). The treated water is taken out from time to time and used as, for example, dilution water for preparing a photoresist developer by a lithography method.

In this pure water production apparatus, the temperature of the raw water is made relatively high at 40 ° C. to 45 ° C. by the heat exchanger 203 for heating, thereby preventing a decrease in the amount of permeate due to slime contamination in the RO device 205 and improving the thermal efficiency. Improvements and prevention of thermal deterioration of the ion exchange resin are attempted.
JP-A-10-309575

  However, in the pure water production apparatus described in Patent Document 1, since the temperature of raw water entering the RO apparatus 205 is as high as 40 ° C to 45 ° C, slime contamination can be prevented as described above, but the standard design of a reverse osmosis membrane The temperature is 25 ° C., and if the water temperature changes, the amount of permeated water, water quality, etc. naturally vary. In addition, the allowable temperature of the membrane is generally said to be 45 ° C, but in addition to being considered to be suppressed to about 30 ° C or less from the viewpoint of deterioration, the temperature of the treated water is stabilized stably with high accuracy. There is a problem that can not be.

  Moreover, there is a problem that the energy consumption in the heat source of the heat exchanger 203 for heating that makes the temperature of the raw water 40 to 45 ° C. is large.

  Further, although ion components in the raw water can be removed by the ion exchange equipment 207, since the removal of carbon dioxide and oxygen dissolved in the raw water is insufficient, dilution water for creating a photoresist developer in the lithography method is used. When used as a carbonic acid, there is a problem that carbonates are formed, which may lead to poor development of the photoresist.

  In view of the above-mentioned conventional problems, the present invention can stabilize the temperature of the produced treated water (pure water) accurately and uniformly, and can also be used for a refrigerating apparatus for an air conditioner such as a factory, an air compressor, and a boiler. It aims at providing the pure water manufacturing method and apparatus with small energy consumption by utilizing waste heat, such as an apparatus. Furthermore, it aims at providing the pure water manufacturing method and apparatus which can remove the carbon dioxide and oxygen which are melt | dissolved in raw | natural water.

The pure water production method of the present invention is a pure water production method for producing pure water by passing raw water whose temperature is controlled through a plurality of heat exchangers through an RO device, the temperature of the raw water in the raw water tank and the water receiving tank , and The water level of the raw water in the water receiving tank is detected by detecting the water level in the water receiving tank and controlling the heat output of multiple heat exchangers and the amount of raw water supplied to the water receiving tank according to the detected temperature and the detected water level. In addition, the water level is controlled to a predetermined value, and raw water is supplied from the water receiving tank to the reverse osmosis membrane separation device.

  According to this configuration, the water receiving tank is configured to control the heat output of the plurality of heat exchangers according to the raw water temperature in the raw water tank provided in the previous stage of the plurality of heat exchangers and in the water receiving tank provided in the previous stage of the RO device. By controlling the temperature of the raw water to a predetermined value, the efficiency of the RO device is kept optimal, the amount of permeated water (treated water) and water quality are stabilized, and the treated water produced by the RO device (pure water) It is possible to stabilize the temperature of water) accurately and constantly.

  Further, if at least one of the brine waste heat, the refrigeration waste heat, the compressor waste heat and the boiler waste heat of the RO device is supplied to the plurality of heat exchangers, a heat source exclusively for controlling the raw water is provided. Compared to the case, energy saving can be achieved by reducing the energy consumption, which can contribute to the reduction of the amount of carbon dioxide that is one of the causes of global warming.

The pure water production apparatus of the present invention is a pure water production apparatus for producing pure water by passing raw water whose temperature is controlled through a plurality of heat exchangers through an RO device, and the supply amount of the raw water tank and the heat medium is reduced. A supply pump that connects a plurality of heat exchangers each provided with a regulating valve to be adjusted, a water receiving tank, and an RO device in this order, and feeds raw water from the raw water tank to the water receiving tank via the plurality of heat exchangers And a controller that controls the adjustment valves of the plurality of heat exchangers according to a first water temperature sensor that detects the temperature of the raw water in the raw water tank and a second water temperature sensor that detects the temperature of the raw water in the water receiving tank The control unit controls the feed amount of the raw water by the supply pump to the water receiving tank in accordance with a water level sensor that detects the water level of the raw water in the water receiving tank .

  According to this configuration, the control unit controls the control valves of a plurality of heat exchangers and performs the pure water manufacturing method, so that the efficiency of the RO device is maintained optimally, and the amount of permeate (treated water) and water quality are maintained. And the temperature of the treated water (pure water) produced by the reverse osmosis membrane separation device can be stabilized with high accuracy and constant.

  Moreover, by supplying at least one of the heat medium heated by the brine waste heat, the refrigeration waste heat, the compressor waste heat and the boiler waste heat (steam) of the RO device to the plurality of heat exchangers, the raw water is exclusively used. Compared with the case where a heat source (heater, boiler, etc.) is provided for controlling the energy consumption, the energy consumption can be reduced.

  In addition, by providing a deaeration device that degass raw water using boiler waste heat as a heat source on the downstream side of multiple heat exchangers, while reducing energy consumption without newly providing a heat source, Dissolved carbon dioxide and oxygen can be removed.

According to the pure water production method and apparatus of the present invention, depending on the raw water temperature in the raw water tank provided in the previous stage of the plurality of heat exchangers and in the water receiving tank provided in the previous stage of the RO device, for an air conditioner such as a factory. Optimizing the efficiency of RO equipment by controlling the temperature of raw water in the water receiving tank to a predetermined value by exchanging heat with multiple heat exchangers using waste heat from refrigeration equipment, air compression equipment, boiler equipment, etc. The amount of permeated water (treated water) and water quality can be stabilized, and the temperature of treated water (pure water) produced by the RO device can be stabilized with high accuracy and constant.
In addition, the control unit controls the operation of the inverter according to the detected water level and drives the supply pump to control the amount of raw water supplied to the water receiving tank so that the water level in the water receiving tank is always maintained constant. Can do.
Furthermore, the heat outputs of a plurality of heat exchangers using waste heat can be adjusted as appropriate according to the operation control value for the inverter.
In addition, the raw water in the water receiving tank has its water level and temperature controlled to be constant with high accuracy, and the raw water in the water receiving tank is taken out by the RO device and pure water is separated by the reverse osmosis membrane. The treated water (pure water) can be supplied to a lithography process or the like for use as, for example, dilution water for preparing a photoresist developer in a lithography method.

  Hereinafter, an embodiment of the pure water production method and apparatus of the present invention will be described with reference to FIG.

  In FIG. 1, the pure water production apparatus of the present embodiment performs a necessary pretreatment such as removing raw water from the raw water tank 1 and preventing the slime from adhering to the reverse osmosis membrane in the pretreatment tank 2. The treated raw water is sequentially passed through the first to fourth heating heat exchangers 41, 42, 43, and 44 by the supply pump 3, and then passed through the deaeration device 5 to supply the raw water heated to a predetermined temperature. It supplies to the RO apparatus 7 through the water receiving tank 6 provided in the front | former stage of RO apparatus 7, performs the separation process of a pure water in the reverse osmosis membrane of the RO apparatus 7, and processes the processed water (pure water) after a process to lithography It is comprised so that it may send to etc.

  The raw water tank 1 is provided with a first water temperature sensor 11 that detects the water temperature of the raw water, and the detected first water temperature detection signal t <b> 1 is input to the control unit 20. Further, the water receiving tank 6 is provided with a second water temperature sensor 12 for detecting the water temperature of the raw water and a water level sensor 13 for detecting the water level of the raw water, and the detected second water temperature detection signal t2 and the water level detection signal h are controlled. Is input to the unit 20. In addition, a use water amount signal w is also input to the control unit 20. The use water amount signal w can be detected by a flow rate sensor (not shown) of the outflow rate to the use side in the lithography process or the like.

  The control unit 20 is configured to output a control signal i1 to an inverter 31 that drives the supply pump 3, and to control the operation of the supply pump 3.

  The first heating heat exchanger 41 heats raw water with waste heat of brine (washing water) used for cleaning the reverse osmosis membrane of the RO device 7, and is a brine pipe to which brine is supplied from the RO device 7. 111 is connected. The brine pipe 111 is provided with an adjustment valve 121 that adjusts the flow rate of the brine to adjust the heat output of the first heating heat exchanger 41. A valve control unit 131 that drives the valve body is connected to the adjustment valve 121. The temperature of the brine supplied from the RO device 7 is 25 ° C., for example.

The second heating heat exchanger 42 heats the raw water with the waste heat of the refrigeration apparatus 101 existing in the factory where the RO device 7 is installed, and is supplied by the heat medium that has received the waste heat of the refrigeration apparatus 101. It is connected to the heat medium piping 112 to be performed. The heat medium guided to the second heating heat exchanger 42 is a heat medium heated by the evaporator of the refrigeration cycle of the refrigeration apparatus 101. The heat medium pipe 112 is provided with an adjustment valve 122 that adjusts the heat output of the second heat exchanger 42 by adjusting the flow rate of the heat medium, and drives the valve body to the adjustment valve 122. A valve control unit 132 is connected. The temperature of the heat medium supplied from the refrigeration apparatus 101 is 28 ° C., for example. As the heat medium, it is possible to use heated waste water from refrigeration apparatus 101, industrial water, well water, city water, a refrigerant or the like.

  The third heating heat exchanger 43 heats the raw water by the waste heat of the compressor device 102 existing in the factory where the RO device 7 is installed, and is supplied by the heat medium that has received the waste heat of the compressor device 102. Is connected to the heat medium pipe 113. The heat medium pipe 113 is provided with an adjustment valve 123 that adjusts the flow rate of the heat medium to adjust the heat output of the third heating heat exchanger 43, and drives the valve body to the adjustment valve 123. A valve control unit 133 is connected. The temperature of the heat medium supplied from the compressor device 102 is 32 ° C., for example. As the heat medium, heated waste water, industrial water, well water, city water, refrigerant, or the like from the compressor device 102 can be used.

  The fourth heating heat exchanger 44 heats the raw water by the boiler device 103 existing in the factory where the RO device 7 is installed when the temperature of the raw water in the previous stage of the RO device 7 is equal to or lower than a predetermined temperature. Yes, it is connected to a heat medium pipe 114 to which a heat medium that has received waste heat from the boiler device 103 is supplied. The heat medium pipe 114 is provided with an adjusting valve 124 for adjusting the heat output of the fourth heating heat exchanger 44 by adjusting the flow rate of the heat medium. The adjusting valve 124 drives a valve body. A valve control unit 134 is connected. The temperature of the heat medium supplied from the boiler device 103 is 120 ° C., for example. As the heat medium, heated industrial water, well water, city water, refrigerant, or the like from the boiler device 103 can be used. Further, instead of the heat medium, excess steam of the boiler device may be supplied to the fourth heating heat exchanger 44.

  The deaeration device 5 degasses carbon dioxide and oxygen dissolved in the raw water. To extend the life of the RO device 7, the deaeration device 5 is provided in front of the RO device 7 in advance. Carbon dioxide and oxygen dissolved in the water can be deaerated to a predetermined dissolved concentration or less.

  The control unit 20 outputs control signals v1, v2, v3, v4 to the valve control units 131, 132, 133, 134 of the first to fourth heating heat exchangers 41, 42, 43, 44, and the first to fourth heating exchangers 41, 42, 43, 44. The fourth heating heat exchangers 41, 42, 43, and 44 are configured to control heat outputs.

  In the above configuration, the raw water in the raw water tank 1 is subjected to the necessary pretreatment in the pretreatment tank 2, and then the first to fourth heating heat exchangers 41, 42, 43, 44 are supplied by the supply pump 3. To the deaerator 5, the dissolved carbon dioxide and dissolved oxygen are degassed and fed to the water receiving tank 6. In the water receiving tank 6, the water level of the stored raw water is detected by the water level sensor 13, and the water level detection signal h is input to the control unit 20. The control unit 20 controls the operation of the inverter 31 based on the water level detection signal h, and drives the supply pump 3 to control the amount of raw water supplied to the water receiving tank 6 so that the water level of the water receiving tank 6 is always maintained. Maintained constant.

  Further, the temperature of the raw water in the raw water tank 1 is detected by the first water temperature sensor 11, and the first water temperature detection signal t 1 is input to the control unit 20. Further, the water temperature of the raw water in the water receiving tank 6 is detected by the second water temperature sensor 12, and the second water temperature detection signal t <b> 2 is input to the control unit 20. Based on these water temperature detection signals t1, t2, the control unit 20 controls the operation of the valve control units 131, 132, 133, 134, 135.

For example, in the winter season , when it is detected that the temperature of the raw water in the raw water tank 1 is 5 ° C. and the temperature of the raw water in the water receiving tank 6 is 25 ° C. , the controller 20 controls all the valve controllers 131, 132, 133. , 134 to output control signals v1, v2, v3, v4 for commanding the full opening of the valve body to maximize the supply amount of the heat medium to the first to fourth heating heat exchangers 41, 42, 43, 44. To do. As a result, the heat output of the first to fourth heating heat exchangers 41, 42, 43, 44 is maximized, the temperature of the raw water heated by the first heating heat exchanger 41 is 6.5 ° C., and The temperature of the raw water heated by the second heating heat exchanger 42 becomes 14 ° C., the temperature of the raw water heated by the third heating heat exchanger 43 becomes 25 ° C., and the fourth heating heat exchanger 44. Then, the temperature of the raw water is supplementarily maintained at 25 ° C., so that the temperature of the raw water at the inlet of the RO device 7 that has passed through the water receiving tank 6 becomes 25 ° C. ± 0.5 ° C.

Further, for example, when it is detected that the water temperature of the raw water in the raw water tank 1 is 15 ° C. and the water temperature of the raw water in the water receiving tank 6 is 25 ° C. in spring or autumn, the control unit 20 performs the first, second and The control signals v1, v2, and v4 for instructing the valve control units 131, 132, and 134 of the fourth heating heat exchangers 41, 42, and 44 to be fully closed are output, while the third heating heat exchanger 43 is output. A control signal v3 for instructing the valve control unit 133 to fully open the valve body is output. Thus, the heat output of the first, second, and fourth heating heat exchangers 41, 42, 44 is stopped, while the heat output of the third heating heat exchanger 43 is maximized. Thereby, the temperature of the raw water heated with the 3rd heating heat exchanger 43 will be 25 degreeC, and the temperature of the raw water at the entrance of RO apparatus 7 which passed through the water receiving tank 6 will be 25 degreeC +/- 0.5 degreeC.

For example, in the summer, when it is detected that the temperature of the raw water in the raw water tank 1 is 29 ° C. and the temperature of the raw water in the water receiving tank 6 is 29 ° C. , the controller 20 controls all the valve controllers 131 and 132. The control signals v1, v2, v3, v4 for instructing the valve body to fully close to 133, 134 are output, and the supply amount of the heat medium to the first to fourth heating heat exchangers 41, 42, 43, 44 To stop. As a result, the heat output of the first to fourth heating heat exchangers 41, 42, 43, and 44 becomes zero, and the heat exchange in the first to fourth heating heat exchangers 41, 42, 43, and 44 is unnecessary. And

As described above, by controlling the heat output of the first to fourth heating heat exchangers 41, 42, 43, and 44 according to the water temperature of the raw water tank 1 and the water temperature of the water receiving tank 6 by the control unit 20, By stably controlling the temperature of the raw water to a predetermined temperature, the raw water heated to the predetermined temperature can be supplied to the RO device 7 via the water receiving tank 6 disposed in the preceding stage of the RO device 7. it can. Note that the heat outputs of the first to fourth heating heat exchangers 41, 42, 43, 44 may be appropriately adjusted according to the water usage signal w or the operation control value for the inverter 31.

  Thus, the waste heat of the brine of the RO device 7 is used for the heat output of the first heating heat exchanger 41, the waste heat of the refrigeration device 101 is used for the heat output of the second heating heat exchanger 42, By using the waste heat of the compressor device 102 as the heat output of the third heating heat exchanger 43 and preliminarily using the heat output of the fourth heating heat exchanger 44, the heat output is obtained by a dedicated heat device. Compared with the case where it produces | generates, a significant energy consumption can be reduced. Table 1 is a table showing the waste heat use energy that uses each waste heat and the necessary energy required for heating the raw water when the pure water production apparatus of this embodiment operates. Table 1 shows the energy used and the required energy during normal operation and during recovery NG. Here, the steady state refers to a case where wastewater such as heated industrial water in an amount necessary for heating raw water can be recovered. Moreover, at the time of collection | recovery NG, it means the case where the waste_water | drain, such as the heated industrial water of the quantity required for the heating of raw | natural water, cannot be collect | recovered.

  As is clear from Table 1, both the energy required for heating raw water is provided by RO brine waste heat, refrigeration equipment waste heat, compressor waste heat, and boiler waste heat both during steady state and during recovery NG. Can do. For example, when the waste heat of the compressor is used, 2,318 tons of carbon dioxide emissions can be reduced in one year as compared with the case where the necessary energy is obtained from city gas and electric power. Further, when the waste heat of the turbo refrigeration apparatus is used as the refrigeration apparatus, it is possible to reduce 700 tons of carbon dioxide emissions in one year compared to the case where the necessary energy is obtained with city gas and electric power. That is, by using the waste heat of the compressor and the waste heat of the turbo refrigeration apparatus, about 3,000 tons of carbon dioxide emissions can be reduced, and as a result, an energy saving effect of 1.3% can be achieved.

  The raw water heated to 25 ° C. after the dissolved carbon dioxide and oxygen are removed by the deaerator 5 is fed to the water receiving tank 6. Thus, the temperature of the raw water in the water receiving tank 6 is accurately maintained at a predetermined temperature of 25 ° C. ± 0.5 ° C.

Pure water raw water thus receiving tank 6, the water level and temperature are controlled to be constant with high precision, the raw water in the receiving tank 6 is at the reverse osmosis membrane is taken out to the R O 7 The treated water (pure water) is supplied to a lithography process or the like for use as, for example, dilution water for preparing a photoresist developer in a lithography method. At that time, since the temperature of the treated water (pure water) is controlled with high accuracy and constant, the concentration of the developer and the like can be controlled with high accuracy and constant, and efficient and accurate processing can be performed. It can be carried out. In addition, since the dissolved carbon dioxide and dissolved carbon in the treated water (pure water) are highly removed, the photoresist is developed with high accuracy without causing defective development of the photoresist due to the carbonate. Can be processed.

  Note that the deaeration device 5 does not necessarily have to be installed in the pure water production device, and in this case, the raw water from the fourth heating heat exchanger 44 may be configured to directly flow into the water receiving tank 6. . In this case, the control unit 20 controls the heat output of the first to fourth heating heat exchangers 41, 42, 43, 44 in response to the first water temperature detection signal t1 and the second water temperature detection signal t2, What is necessary is just to control the temperature of the raw | natural water in the water receiving tank 6 so that it may become a predetermined value.

  In addition, the first to fourth heating heat exchangers 41, 42, 43, and 44 are not necessarily installed in the pure water production apparatus, and the number of heat exchangers for heating the raw water is required energy. It can be changed accordingly. Moreover, it is not necessary to use all the waste heat of the refrigeration apparatus 101, the compressor apparatus 102, and the boiler apparatus 103, and at least one waste heat of the refrigeration apparatus 101, the compressor apparatus 102, and the boiler apparatus 103 may be used. Moreover, you may utilize the waste heat of another thermal apparatus.

  The pure water production method and apparatus according to the present invention includes the heat output of a plurality of heat exchangers according to the raw water temperature in the raw water tank provided in the previous stage of the plurality of heat exchangers and in the water receiving tank provided in the previous stage of the RO device. By controlling the temperature of the raw water in the water receiving tank to a predetermined value, the efficiency of the RO device is kept optimal, the amount of permeate (treated water) and water quality are stabilized, and the RO device is manufactured. The temperature of the treated water (pure water) can be stabilized with high accuracy and constant.

The schematic block diagram of the pure water manufacturing apparatus of one Embodiment of this invention. The schematic block diagram of the pure water manufacturing apparatus of a prior art example.

Explanation of symbols

1 Raw water layer 6 Receiving tank 7 RO device (reverse osmosis membrane separation device)
DESCRIPTION OF SYMBOLS 11 1st water temperature sensor 12 2nd water temperature sensor 20 Control part 41 Heat exchanger for 1st heating 42 Heat exchanger for 2nd heating 43 Heat exchanger for 3rd heating 44 Heat exchanger for 4th heating

Claims (4)

A pure water production method for producing pure water by passing raw water whose temperature is controlled through a plurality of heat exchangers through a reverse osmosis membrane separation device, the temperature of the raw water in the raw water tank and the water receiving tank, and the raw water in the water receiving tank The water level is detected, and the temperature and water level of the raw water in the water receiving tank are set to predetermined values by controlling the heat output of multiple heat exchangers and the amount of raw water supplied to the water receiving tank according to the detected temperature and the detected water level. A method for producing pure water, comprising controlling and feeding raw water from a water receiving tank to a reverse osmosis membrane separation device.   2. The pure water production according to claim 1, wherein at least one of brine waste heat, refrigeration waste heat, compressor waste heat and boiler waste heat of the reverse osmosis membrane separator is supplied to the plurality of heat exchangers. Method. A pure water production apparatus for producing pure water by passing raw water whose temperature is controlled through a plurality of heat exchangers through a reverse osmosis membrane separation apparatus, each comprising a raw water tank and an adjustment valve for adjusting the supply amount of the heat medium. A plurality of heat exchangers, a water receiving tank, and a reverse osmosis membrane separator are connected in this order, and a supply pump for supplying raw water from the raw water tank to the water receiving tank through the plurality of heat exchangers is provided. a first temperature sensor for detecting the temperature of the raw water inside, a control unit for controlling the control valve of the plurality of heat exchangers in accordance with the second water temperature sensor for detecting the temperature of the raw water in the water tank is provided, the control The unit controls the amount of raw water supplied by a supply pump to the water receiving tank according to a water level sensor that detects the water level of the raw water in the water receiving tank .   The heat exchanger is supplied with at least one of a heat medium heated by brine waste heat, refrigeration waste heat, compressor waste heat, and boiler waste heat of a reverse osmosis membrane separator. 3. The pure water production apparatus according to 3.

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